This study was conducted during the summer season of 2009 and 2010 at Barrage Horticultural Research Station, Kalubia governorate. The study included two experiments on two bean cultivars (Paulista and Nebraska). The first was to investigate the response of Paulista cultivar (green yield) to seed size (large and small) and planting dates (the first week of February, March and April). The second experiment was to investigate the response of Nebraska cultivar (dry yield) to seed size (large and small) and planting dates (first week of February, March and April). Data were recorded on plant height, number of branches/plant, dry weight of leaves/plant, total green yield, pod weight, pod length, pod thickness, pod width, weight of 100 seed, seed germination percentage, total protein and potassium percentage for Paulista cultivar in the first experiment. While, the characters studied for Nebraska cultivar in the second experiment were plant height, number of branches/plant, dry weight of leaves/plant, total dry seed yield, number of seed/pod, weight of 100 seed, seed germination percentage, total protein, nitrogen and potassium percentages. Regarding results of the first experiment, sowing large seed size from Paulista cultivar gave higher values of plant height, number of branches, dry weight of leaves/plant, total green yield, pod weight, pod characters, weight of 100 seed and seed germination percentage than those obtained from small seed size in both seasons. Sowing in the first week of March gave the highest value of plant height, number of branches, dry weight of leaves/plant, total green yield, pod weight, pod characters, weight of 100 seed, seed germination percentage and potassium percentage in both seasons. Using large seeds and sowing in the first week of March gave the highest values for dry weight of leaves/plant, total green yield, pod weight and seed germination percentage. Concerning the second experiment, sowing with large seeds from Nebraska cultivar gave the high values in most traits, i.e. plant height, number of branches, dry weight of leaves/plant, total dry seed yield, number of seeds/pod, weight of 100 seed, seeds germination percentage, nitrogen percentage and total protein, compared to small size. Sowing Nebraska cultivar in the first week of March gave the highest values of plant height, number of branches, dry weight of leaves/plant, total dry seed yield, number of seeds/pod, weight of 100 seed, seed germination percentage, total protein and nitrogen and potassium percentage. For this study it can be concluded that using the large seed size from the cultivars Paulista (green yield) and Nebraska (dry yield) for the growing and planting in the first week from March gave the highest total yield and yield quality.