This work was carried out at Gemmeiza Agriculture Research Station Farm (Gharbeia Governorate) during 2006/2007 and 2007/2008 onion growth seasons, to study the effect of four irrigation regimes (one, two, three and four irrigations) and behavior of six new onion cultivars selected by Onion Research Section (Composite 9, Giza white, Behairy no pink, 1866 Globe, Giza Red and Giza 20) on growth, earliness bulb yield (ton/fed) and storability of bulbs as well as water consumption. A separate experiment for each irrigation treatment was used with Randomize Complete Blocks Design in four replication. The main obtained results from this investigation cane be summarized as follows: 1-   Giving onion plants 2-3 irrigations increased average plant length (cm), number of leaves/plant, days to maturity, total yield (ton/fed), marketable yield (ton/fed) and culls yield (ton/fed). Whereas, decreasing bulbing ratio, dry matter percentage of plants, percentage of total loss in marketable yield during storage period of four months were increased with increasing of number irrigations to 2-3 irrigations. One, two and three irrigations saved 55.17 and 53.23 % (about 1349.63 and 1238.84 m³/fed), 35.13 and 37.85 % (about 861.95 and 880.84 m³/fed) and 17.84 and 15.54 % (about 436.41 and 3611.67 m³/fed) compared to giving four irrigations. 2-   Giza Red and Giza 20 cultivars increased plant length (cm), number of leaves/plant, percentage of dry matter in plants, number of days to maturity, total yield (ton/fed) and marketable yield (ton/fed) as compared with other cultivars . Whereas, Giza White and Comp. 9 cultivars caused a decrease in plant height (cm), number of leaves/plant, fresh weight/plant and bulbing ratio. The higher culls bulbs was associated with 1866 Globe and Giza 20. Whereas, Giza White cultivar produced less culls bulbs (t/fed). The highest total loss weight during storage period of four months was abserved with Comp. 9. Whereas, the less loss of weight was observed with Giza Red and Giza 20. Comp. 9 cultivar. consumed the highest irrigation water (1836.45 and 1785.58 m³/fed) in both seasons. Whereas, Giza 20 and Behairy no Pink cultivars consumed less irrigation water. 3-   The interaction between irrigation regimes and cultivars showed significant   effects on marketable bulb yield (ton/fed) and total culls (ton/fed) in 2006/2007 season. The maximum marketable yield was observed with the treatment combination of giving 3-4 irrigations to Giza 20 cultivar. The maximum total culls bulbs (5.73 ton/fed) was observed under the treatment combinations of four irrigations and 1866 Globe cultivar. Generally, it cane be concluded that giving 2-3 irrigations to Giza Red and Giza 20 cultivars saved suitable quantity of irrigation water and produced the highest onion bulbs yield with best quality.