Two field experiments were conducted in the two seasons of 2005 and 2006 at the experimental farm of El Sirw Agriculture Research Station, Dammeitta. Egypt to study the response of some inbred and hybrid rice varieties (Sk 2034H .Sk2025H .SKZOSBH .Giza 177.Giza 178 and Sakha 104) to various nitrogen levels ( O. 60. 120. 180and 240 kg N [ha ).The experimental soil was clay with ECe levels of 7.89 and 8.25dS m'1 in 2005 and 2006 seasons respectively. The growth .yield attributes. yield and nitrOQen— use efficiencies of the tested rice varieties under the aforementioned nitrogen levels were determined. The tested rice varieties showed great variation in their growth .yield attributing characters and grain and straw yields as well as their nitrogen use efficiencies . Hybrid rice variety of Sk2034H surpassed other tested rice varieties while the worst one was the salt sensitive variety Giza 177. Hybrid rice variety SK2034H had higher nitrogen-use efficiency than inbreeds. except physiological efficiency index of absorbed nitrogen (PIEN) where. its highest value was given by Giza 177 Increasing nitrogen levels significantly improved growth .yield attributes and grain and straw yields. Furthermore. each unit increase in nitrogen levels led to significant increase in growth. yield attributing characters and yield of rice. The maximum grain yield was produced with the addition of 240 kg N/ ha. The nitrogen uptake . nitrogen use efficiency (NUE). apparent recovery (%) and physiological   efficiency index of absorbed nitrogen (PEIN) were significantly higher at lower nitrogen level and decreased significantly with increasing N levels . The response of the investigated inbred and hybrid rice varieties to nitrogen levels significantly varied . The most rice varieties significantly responded to nitrogen up to 180 kg NI ha . The inbred rice varieties Giza 177 and Sakha 104 significantly responded to nitrogen level up to 240 kg Nlha.