This investigation was carried out at the Experimental Farm of Assiut University during  2007/2008 and 2008/2009 seasons to study the effect of irrigation interval on growth and yield of Balady and Black Beauty eggplant cultivars .On the base of  water requirements for the eggplant crop , the amount of watering was calculated  from 4750 m³ /fed. Along 145 days present the eggplant growing season i.e.0.1m³ /m²and applied at 12,18,24 and 30 days intervals. Black Beauty cv. showed a significantly higher root fresh weight , early and total yield per plot and per feddan in both seasons of the study as an average of all tested irrigation interval.  Irrigation interval showed a significant effect on total yield as 12 day irrigation interval resulted in higher root fresh weight and total yield. Early yield did not show significant response to irrigation interval. Longer irrigation intervals significantly shortened the period to the first flower . This response was more clear in Black Beauty cv. than Baladay cv. Irrigation every 12 days gave high significantly the highest values of stem length and the greatest  number of branches per plant in the two cultivars in both seasons.
Key words: Eggplant, water stress, irrigation interval, yield.