The purpose of this study was to evaluate the effect of delayed harvest upon soybean seed quality in Palotina, State of Paraná, Brazil; Twenty and nineteen soybean cultivars were tested in 1982 and 1983, respectively. Five harvests were made, starting on R-8 stage, and 7, 14, 21 and 28 days after the R-8 stage. The seed quality was evaluated through standar germination test and visual seed quality test. The results indicated that occurrence of rains which accompained delayed harvests was the most important factor in soybean seed quality. The climatic conditions in Palotina didn?t show, favorable for soybean seed production therefore, for this purpose, the cultivars should be selected, and delayed harvest is harmful. Based on the results of this study, the following cultivars are indicated: Paraná, lapó, IPB-7768, FT-2, FT-3, Bossier, BR-1, Viçoja, FT-4, Santa Rosa and UFV:1.