Two field experiments were conducted during the two successive seasons of 2007/2008 and 2008/2009, at Sids Agricultural Research Station, Bani Sweif Governorate. The objectives of this investigation was aimed to studies productivity and storage quality of some onion cultivars i.e. (Shandaweel 1, Giza 6 Mohassan and Giza 20), when cultivated by two cultivating methods (using sets and seedlings), and using three onion cultivars under Middle Egypt conditions. The obtained results could be summarized as the following: 1. The shortest season was obtained by Shandaweel 1 cultivar followed by Giza 6 Mohassan while Giza 20 appeared the longest season, in both seasons. Giza 20 cultivar appeared the highest values of average bulb weight and single bulbs%, while Shandaweel 1 cultivar appeared the lowest values. Giza 20 cultivar attained the lowest values of double bulbs%, while Shandaweel 1 attained the highest values. Giza 6 Mohassan appeared the minimum values of bolter%, whereas shandaweel1 appeared the maximum values. The maximum values of marketable yield/fed and total yield/fed were obtained by Giza 20 cultivar, while the lowest values were obtained by Shandaweel 1. 2. Planting onion by seedlings gave higher values of average bulb weight and single bulbs% as compared to planting by sets in both seasons. Seedlings cultivating method gave lower values of double bulbs% and bolters% as compared to sets cultivating method.  The values of marketable yield/fed and total bulb yield/fed of onion under seedlings cultivating method surpassed those under sets cultivating method 3. The lowest values of decayed and sprouted bulbs% were obtained by the combination between seedlings cultivating method and Giza 6 Mohassan, at all storage periods in both seasons, except for this at 180 days in the first season. 4. Cultivating onion by seedling and using Giza 6 Mohassan cultivar attained the lowest values of bulbs weight loss% at all storage periods, in both seasons. 5. The interaction between onion cultivars and method of cultivation significantly affected single bulbs %, average bulb weight (gm), bolters % and infected bulb. It could be concluded that for maxi mixing onion yield and it is quality during storage by cultivation of Giza 20 cultivar using seedlings method under cultivation of Bani Sweif Governorate.