Themen's400 metres event at the1985 IAAF World Indoor Games was held at thePalais Omnisports Paris-Bercy on 18 and 19 January.
| Gold | Silver | Bronze |
Thomas Schönlebe East Germany | Todd Bennett Great Britain | Mark Rowe United States |
First 2 of each heat (Q) and next 2 fastest (q) qualified for the semifinals.[1]
| Rank | Heat | Name | Nationality | Time | Notes |
|---|---|---|---|---|---|
| 1 | 4 | Todd Bennett | Great Britain | 47.19 | Q |
| 2 | 5 | Amadou Dia Ba |  Senegal | 47.55 | Q |
| 3 | 5 | Phil Brown | Great Britain | 47.60 | Q |
| 4 | 3 | Mark Rowe | United States | 47.70 | Q |
| 5 | 5 | Carlos Reyté |  Cuba | 47.82 | q |
| 6 | 2 | Ángel Heras |  Spain | 47.88 | Q |
| 7 | 2 | Clarence Daniel | United States | 47.96 | Q |
| 7 | 4 | Allan Ellsworth |  Netherlands | 47.96 | Q |
| 9 | 4 | Lázaro Martínez | Cuba | 48.06 | q |
| 10 | 3 | Arjen Visserman | Netherlands | 48.12 | Q |
| 11 | 3 | Allan Ingraham |  Bahamas | 48.14 | |
| 12 | 5 | Isidro del Prado |  Philippines | 48.35 | NR |
| 13 | 4 | Ahmed Abdelhalim Ghanem |  Egypt | 48.77 | |
| 14 | 3 | Ahmed Hamada |  Bahrain | 48.80 | NR |
| 15 | 4 | Abdelali Kasbane |  Morocco | 48.93 | NR |
| 16 | 1 | Thomas Schönlebe | East Germany | 48.95 | Q |
| 16 | 2 | Ali St. Louis |  Trinidad and Tobago | 48.95 | |
| 18 | 1 | René Djédjémel Mélédjé |  Ivory Coast | 49.36 | Q |
| 19 | 4 | Djétenan Kouadio | Ivory Coast | 49.45 | |
| 20 | 5 | Gerry Delaney |  Ireland | 49.83 | |
| 21 | 2 | Mike Okot |  Uganda | 50.19 | |
| 22 | 1 | Aðalsteinn Bernhardsson |  Iceland | 50.37 | |
| 23 | 1 | Khaled Hussain |  Kuwait | 50.50 | NR |
| 24 | 5 | Alberto Izu |  Peru | 51.19 | NR |
| 1 | David Kitur |  Kenya | DNS | ||
| 1 | David Peltier |  Barbados | DNS | ||
| 2 | Nabil Nahri |  Syria | DNS | ||
| 3 | Billy Konchellah | Kenya | DNS | ||
| 3 | Roberto Ribaud |  Italy | DNS |
First 3 of each semifinal (Q) qualified directly for the final.[2]
| Rank | Heat | Name | Nationality | Time | Notes |
|---|---|---|---|---|---|
| 1 | 2 | Thomas Schönlebe | East Germany | 46.62 | Q |
| 2 | 2 | Todd Bennett | Great Britain | 46.69 | Q |
| 3 | 2 | Mark Rowe | United States | 46.70 | Q |
| 4 | 1 | Amadou Dia Ba | Senegal | 47.86 | Q |
| 5 | 1 | Ángel Heras | Spain | 47.89 | Q |
| 6 | 1 | Phil Brown | Great Britain | 47.93 | Q |
| 7 | 1 | Clarence Daniel | United States | 48.01 | |
| 8 | 1 | Arjen Visserman | Netherlands | 48.08 | |
| 9 | 2 | Allan Ellsworth | Netherlands | 48.09 | |
| 10 | 1 | Lázaro Martínez | Cuba | 48.67 | |
| 11 | 2 | René Djédjémel Mélédjé | Ivory Coast | 49.09 | |
| 12 | 2 | Carlos Reyté | Cuba | 49.39 |
| Rank | Name | Nationality | Time | Notes |
|---|---|---|---|---|
 | Thomas Schönlebe | East Germany | 45.60 | WB |
 | Todd Bennett | Great Britain | 45.97 | NR |
 | Mark Rowe | United States | 46.31 | PB |
| 4 | Amadou Dia Ba | Senegal | 46.94 | NR |
| 5 | Phil Brown | Great Britain | 47.84 | |
| 6 | Ángel Heras | Spain | 54.09 |
