The effects of a yard waste compost on densities of plant-parasitic nematodes and forage yield of maize (Zea mays) were determined over three seasons in two sites in north Florida. In each test, the experimental design was a randomized complete block with five replications and three treatments: 269 mt/ha of a yard waste compost C:N ratio = 35:1 to 46:1) applied to the soil surface as a mulch, 269 mt/ha of compost incorporated into the soil, and an unamended control. Of the nematodes found in these sites, Paratrichodorus minor was affected most by compost treatments, with densities at harvest reduced by a compost treatment on at least one sampling date in all three seasons (P </= 0.05). Meloidogyne incognita was not consistently affected by compost application. Densities of Criconemella spp. and Pratylenchus spp. were reduced by compost treatment much more often in the third season than in the first two seasons of the study (P </= 0.05). Forage yield of maize was increased (P </= 0.05) by both compost treatments in every test, with yield increases ranging from 10% to 212% over yield levels in unamended control plots and varying with season (P </= 0.05). Use of yard waste compost on agricultural sites may provide a beneficial amendment for crop production and a convenient means for disposal of a common waste product from urban areas. Effects of this compost with high C:N ratio on nematodes were long-term, often not appearing until the third season of the study.