This study was conducted at Sakha Agricultural Research Station, kafr El_Shiekh, Egypt during 2013 and 2014 growing summer season to determine the effects of three planting dates on seed yield and seed quality of ten soybean genotypes. The planting dates starting from mid-May at 15 days intervals. The soybean genotypes included Giza 22, Giza 35, Giza 111, and Crawford (four commercial soybean cultivars), H 30, H 32, H₂ L₁₂, and DR101(promising lines) and two introductions (Toano and Holladay). The obtained results of the combined data showed that delaying from mid-May to mid-June significantly decreased numbers of days to flowering and maturity from 40.4 and 133.91days, respectively to 34.3 and 122.2 days, and shortened the reproductive growth stage from 93.9 to 88.0 days, along with reducing weight of 100 seeds from 15.92 to 12.39g, and seed yield per feddan from 1.613 to 1.053 ton/fed^-1. On contrary, seed protein content and seed germination were increased from 33.23 and 69.5% to 39.09 and 89.67%, respectively, while oil content was decreased by delaying planting from 23.06 to 19.18%. The soybean genotypes varied in all studied traits, that DR 101 was the latest in flowering and maturity (51.3 and 150.3 days, respectively) and produced the highest 100-seed weight (17.2g), while H30 was the earliest in maturity (115.00 days) and the lowest in 100-seed weight (12.14g). The commercial cultivar Giza 111 produced the highest seed yield (1.625t/fed.). Data showed also that Toano was the best in seed germination over all planting dates with 90.22% as an average, whereas H32 was the bad in seed germination (60.22%). It could be concluded that, Giza 111, Toano and DR 101 could produce acceptable seeds with more than 80% germination when planted during the first half of June, while the earlier genotypes H30, H32, and Giza 35 must be planted around mid-June to produce seeds with acceptable viability.