Cardozo is the son of Rosa María, who claimed that "Óscar has been a very good son and has managed to help us and take us away from poverty".[5] His father is Arnaldo and his parents have five children.[5][6]
Cardozo commenced his professional career with modestClub Atlético 3 de Febrero ofCiudad del Este, participating in theDivisión Intermedia championship in 2003 and forming a partner ship with strikerRoberto Gamarra.[7] In Round 1 of the 2003 season, Cardozo scored in a 1–1 home draw againstCerro Corá.[8] In the following fixture, he scored in a 2–0 home victory againstSportivo Iteño on 11 May.[8] Two weeks later, he netted in a 3–0 home victory againstRiver Plate Asunción on 25 May.[8] Cardozo would not score again until Round 11, where the player scored the only goal in a 1–0 away victory for 3 de Febrero againstCerro Porteño de Presidente Franco on 13 July.[8] The following week, Cardozo would again score against Cerro Corá in a 1–1 away draw on 27 July.[8]
On 10 August, Cardozo scored his first double in a 2–0 home victory againstNacional Asunción.[8] On 7 May, Cardozo would score the only goal for 3 de Febrero as they were defeated 3–1 away against River Plate Asunción on 16 August.[8] In the following fixture, Cardozo would again score, this time in a 1–1 home draw againstPresidente Hayes on 23 August.[8] On 30 August, Cardozo scored in a 5–1 away thrashing againstColegiales, which totaled to five consecutive goals in four matches.[8] Cardozo's last league goal would come in Round 21, when the player netted in a 2–1 away victory againstDeportivo Recoleta on 27 September.[8] 3 de Febrero had finished in 2nd place of the División Intermedia table and were drawn into promotion play-off fixtures.[8] On 12 October, Cardozo scored in 3 de Febrero's 4–2 victory against River Plate Asunción and one week later would score against Cerro Corá in his side's 2–0 victory on 19 October.[8] Cardozo again scored in the following play-off fixture, a 3–2 victory againstGeneral Caballero Zeballos Cué on 25 October.[8] Having won three qualifying promotion play-off fixtures successfully, 3 de Febrero ultimately facedClub Tacuary in a promotion-relegation play-off, which saw the latter win 4–2 on aggregate.[8]
Cardozo scored his first goal of the 2004 División Intermedia season in a 1–0 away victory against Cerro Corá in Round 6 on 2 May, with 3 de Febrero continuing an undefeated run.[9] One week later, Cardozo scored a double againstSportivo San Lorenzo in a 2–0 home victory on 7 May.[9] In the following round, 3 de Febrero suffered their first defeat of the season after 8 eight rounds in a 1–0 away defeat against General Caballero, however, consistent results continued as Cardozo scored in a 1–1 draw in the Superclásico ofAlto Paraná against Cerro Porteño PF one week later on 23 May.[10][9] Cardozo scored his 5th league goal of the season in a 2–1 home victory against Cerro Corá in Round 15 on 9 July.[9] 3 de Febrero had been on a 9-game undefeated streak, which ultimately lasted until Round 18, the last match of the season against Cerro Porteño PF which they narrowly lost 4–3 on 31 July. The match saw Cardozo score his 6th league goal of the season and his final goal as a 3 de Febrero player.[9] Cardozo then joined Nacional Asunción during the 2004 season. Before signing with Nacional Asunción, Cardozo had played in 12 out of 3 de Febrero's 18 league matches, scoring 6 goals, which ultimately saw the club finish in first position of the División Intermedia, with 34 points and having lost just two league matches, and gain promotion to the 2005 Paraguayan Primera División season.[9] Cardozo went on to participate in the second half of the 2004 season for Club Nacional Asunción, participating in the Torneo Clasura.
In 2004, he moved to thetop level withAsunción's Club Nacional, where he quickly established himself as the team's top scorer, scoring 17 overall goals in his last season.
On 21 June 2007, Cardozo officially signed for Portuguese clubBenfica, after being bought for an approximate €9.1 million for 80% of his playing rights[11][12]– this made him the second most expensive signing in the club's history, only surpassed bySimão for whom the club paid €13 million in 2001. Cardozo finishedhis first season with 22 official goals, but Benfica came out empty in silverware. On 22 February 2008, he scored alast-minute goal against1. FC Nürnberg forthe campaign'sUEFA Cup (2–2 away draw, 3–2 aggregate win), thereby keeping his promise of surpassing the 20-goal mark.[13]
In2008–09 Cardozo scored 17 goals, all in theleague, including the equalizer againstPorto on 30 August 2008. He finished second in theBola de Prata race, losing only toNenê ofNacional. In April 2008, Benfica bought out the remaining 20% of his rights for a further €2.5 million, thus investing €11.6 million total in his economic rights.[14]
In the Europa League quarter-finals againstLiverpool, Cardozo scored twopenalties for a 2–1 home win.[18] He also found the net in the second leg atAnfield with afree kick, but in a 1–4 loss and subsequent elimination;[19] as Benfica won the national championship, addingthe year'sdomestic League Cup, he finished with a career-high 38 goals in 47 matches (26 in the domestic league, leading Porto'sRadamel Falcao by only one), partnering well with ArgentineJavier Saviola. On 10 February 2010, Benfica sold 20% of his economic rights toBenfica Stars Fund for €4 million, valuing him at €20 million.[20]
At the end of the2011–12 campaign Cardozo was crowned the Primeira Liga's top scorer for the second time, with 20 goals – joint withBraga'sLima[21] – as Benfica finished in second position. On 10 December 2012, he scored three in a 3–1Lisbon derby win at Sporting (even though one of the goals was initially attributed toMarcos Rojo as anown goal),[22] repeating the feat the following week at home againstMarítimo (4–1), which resulted in him surpassing the 100-goal mark in domestic league play.[23]
On 2 January 2013, Cardozo took hisseason tally to 21 goals in 19 official games after netting three in a 6–0 home routing ofDesportivo das Aves forthe campaign'sTaça de Portugal.[24] On 2 May, he scored his fifth and sixth in eight contests inthe season's Europa League, being crucial to a 3–1 home win againstFenerbahçe in the semi-finals second leg with the subsequent 3–2 aggregate qualification tothe final inAmsterdam.[25] In the decisive match, he netted from the penalty spot in the 68th minute for the 1–1 equalizer againstChelsea, who won it 2–1.[26]
Cardozo was replaced after 70 minutes in thedomestic cup final on 26 May 2013, with Benfica leading 1–0 but then losing 1–2 toVitória de Guimarães.[27] At the end of the game, he angrily confronted managerJorge Jesus, inclusively pushing him; he later apologised for his actions, being fined for half of his monthly salary.[28][29]
Cardozo startedthe new season after his teammates due to the controversy, but soon returned to his scoring ways. His goals against Guimarães,[30]Estoril,[31] and Nacional were vital in keeping Benfica in the race for the title.[32][33] On 9 November 2013, he put three past Sporting in a 4–3 home win forthe domestic cup's fourth round, increasing to 13 the goals he scored against Sporting, surpassingManuel Fernandes in the list of top goalscorers of theLisbon derby.[34][35] In November 2013, an injury ruled him out for2+1⁄2 months.[36] When he returned, he found himself relegated to the bench, with the team now fully adapted to play with Lima andRodrigo.[37] On 1 February, after missing his ninth penalty kick in Primeira Liga, in a match againstGil Vicente, Cardozo became the player with most missed penalties in the competition.[38]
In early August 2014,Trabzonspor announced they were negotiating with Benfica and Cardozo.[40] On 4 August 2014, Cardozo left Benfica and thanked the club by stating, "You will always be in my heart".[41]
On 4 August 2014, Cardozo moved TurkishSüper Lig side Trabzonspor for a €5 million fee, (Benfica received €4 million, the fund €1 million) with a further €1.65 million contingent on performance-related bonuses.[42] He signed a contract with €2.5 million per season plus bonuses.[43]
On 21 August, he scored his first goal for the club, in a 2–0 home win against Russian sideRostov forthe campaign's UEFA Europa League. Cardozo made his league debut in a 1–1 away draw againstİstanbul Başakşehir on 22 September. He came onto the field in the 52nd minute forFatih Atik, and scored a 93rd-minute penalty to equalise.[44]
On 1 December, Cardozo scored his first hat-trick in a 4–1 home victory againstGençlerbirliği. He scored in the 8th, 40th and 65th minutes of the match before being substituted off of the field for Fatih Atik in the 70th minute. Cardozo brought his goal scoring tally to eight goals in nine league appearances.[45] During a group stage match of the2014–15 Turkish Cup, Cardozo scored a double in Trabzonspor's 9–0 home victory againstManisaspor on 25 December.[46]
Cardozo rounded off the season scoring 17 league goals in 29 appearances as Trabzonspor finished in fifth place and qualified for the2015–16 UEFA Europa League second qualifying round. He finished in third place of the Süper Lig top goalscorers list, behindDemba Ba (18 goals) andFernandão (22 goals).
After the 2014–15 season, it was announced that Cardozo would not play in the2015 Copa América for Paraguay due to a back injury, whereupon it was then revealed by his agent that he had been playing through the pain for his club side.[47]
On 31 August 2016, Cardozo joined Greek championsOlympiacos.[48] He scored his first goal in theSuper League Greece on 12 December that year, opening the score in a 2–0 away win overPAS Giannina and thus ending his seven-match goalless run.[citation needed]
On 5 November 2019, he scored the opening goal of Libertad's 4–1 away victory overSol América in theCopa Paraguay semifinals. In the following month, on 4 December, Libertad won their first Copa Paraguay after beatingGuaraní 3–0. Cardozo came on in the 83rd minute of thefinal.[52]
On 21 May 2021, Libertad faced Sol América on the last matchday of the2021 Torneo Apertura with the title on the line, but Cardozo did not play the match due to having tested positive for COVID-19 a few days before.[53] Without him, Libertad lost 0–1, but two days later, the club secured their twenty-first league title after Nacional failed to win their match.[54] Cardozo contributed with nine goals and nine assists during the campaign.[53] On 25 June 2022, Libertad faced fellow title contendersCerro Porteño on the penultimate matchday of the2022 Torneo Apertura, winning the match 1–0 and thus securing their twenty-second league title.[55]
On 3 April 2023, Cardozo scored four goals in a 5–0 trashing of Cerro Porteño, marking his first-ever poker in his professional career, with his final goal of the night being also his 100th with the Libertad shirt in official competitions, thus becoming the second player in the history of Libertad to do so afterJuan Samudio.[56] In doing so at the age of 39 years and 318 days, he became the oldest player to score a poker in the 21st century, surpassingPablo Escobar's record from 2018 by 19 days, as well as the second in history, only behindJosef Bican in 1955, aged 41.[57] In the following month, on 4 May, just 16 days shy from his 40th birthday, Cardozo scored the opening goal in an eventual 1–2 loss toAthletico Paranaense in the2023 Copa Libertadores group stage, thus becoming one of the oldest goalscorers in Copa Libertadores history.[58] Libertad finished third in the group and it was therefore relegated to the2023 Copa Sudamericana final stages, where on 13 July, Cardozo scored a last-minute winner againstAtlético Tigre in the first leg of theknockout round play-offs in an eventual 3–1 aggregate win.[59] On 20 October, he scored his 400th career goal in a 3–0 win overSportivo Ameliano.[60] On 26 November, Cardozo scored a brace in a 3–1 comeback victory overClub Olimpia, the first from the penalty spot and the second with a free-kick, while Libertad's third goal was scored by his fellow 40-year-old attacking partnerRoque Santa Cruz.[61]
At the end of the season, the 40-year-old Cardozo emerged as the top scorer of the2023 Paraguayan Primera División season and with ease, being the top scorer in both the Apertura tournament (10 goals) and the Clausura tournament (11 goals) for a total of 21 goals in the Paraguayan league, which was 7 more than his closest pursuer, the 23-year-old Gustavo Aguilar.[62] Furthermore, Cardozo was also champion in both tournaments and then helped Libertad win the Paraguay Cup to complete the domestic treble.[62] On 5 December 2023, theParaguayan Football Association elected him as the best player in Paraguay, becoming the oldest player to do so in the process.[63]
On 30 May 2024, Cardozo scored a first-half equaliser in an eventual 2–1 win over Uruguay'sClub Nacional in the last match of the2024 Copa Libertadores group stage, becoming, at the age of 41 years and 10 days, the fourth-oldest player to score in the Copa Libertadores.[64] The following week, on 5 June 2024, he scored a free-kick against Club Olimpia to help his team to a 3–1 win.[65] Later that year, on 29 November 2024, Cardozo scored a stoppage-time equaliser from the penalty spot in an eventual 3–2 victory over Cerro Porteño in the Torneo Apertura; this was his 132nd goal for Libertad, overtaking Juan Samudio to become the club's all-time top scorer.[66] The following week, on 6 December, he played in the final of the2024 Copa Paraguay, coming off the bench in the second-half to help his side to a 1–0 win over Nacional.[67] In total, he scored 12 goals and made two assists in 47 games for Libertad in 2024.[67]
On 27 May 2025, just seven days after turning 42, Cardozo converted a penalty in a 2–2 draw withAlianza Lima, whose forward 41-year-oldPaolo Guerrero also scored, marking the first time in the history of Copa Libertadores that two 40-year-old players scored for each team in the same match.[68] This goal also saw him become the third-oldest goalscorer in the history of the Copa Libertadores, only behind his teammate Roque Santa Cruz in 2024 (42 years and 8 months) andZé Roberto in 2017 (42 years and 10 months).[69]
Cardozo scored two goals in the2010 FIFA World Cupqualification stages, as Paraguay qualified for the finals in South Africa. On 29 June 2010, he netted the winning penalty in the shootout againstJapan (5–3 victory), asLa Albirroja qualified for theWorld Cup quarter-finals for the first time ever.[70] In the following game, however, with the score at 0–0, he missed a 59th-minute penalty againstSpain in a 0–1 defeat against the eventual champions.[71]
Cardozo was overlooked by coachGerardo Martino for the2011 Copa América squad, despite scoring 23 official goals for Benfica in 2010–11. Having already been included byRamón Díaz in theAlbirroja preliminary squad, Cardozo would again miss out2015 Copa América due to a back injury.[47] On 16 June 2019, aged 36, he scored againstQatar inCopa América and became the oldest player in Paraguay's history to score in that competition, breakingDelfín Benítez Cáceres' 1946 record.[72]
In spite of the same surname, a similar nickname and physical resemblance, he is not related toRamón Cardozo (known as "Tacuarita"), who is also a footballer and a forward.[73] He obtained Portuguese citizenship in November 2014.[74]
^"Clássico é Cardozo marcar ao Nacional" [A classic is Cardozo scoring against Nacional].Record (in Portuguese). 28 October 2013.Archived from the original on 23 June 2018. Retrieved23 June 2018.
^"Comunicado" [Announcement](PDF).CMVM (in European Spanish). SL Benfica. 4 August 2014. Archived fromthe original(PDF) on 8 August 2014. Retrieved19 October 2021.