2011) Effect of irrigation regimes on water use efficiency and tomato yield (Lycopersicon esculentum Mill.) grown in an arid environment, Archives of Agronomy and Soil Science, 57:1, 105-114, This study was conducted to determine the influence of irrigation regimes on yield of two tomato cultivars -TY-DANA and GS12. Experimental treatments were three irrigation intervals (2, 4, and 6 days), and three irrigation quantities (50%, 75%, and 100% of pan evaporation [Ep]). The total yield increased with increasing amount of irrigation water for both cultivars. The total yield increased about 10% and 17% for 100% of Ep treatment compared with 50% Ep treatment for TY-DANA and GS12 cultivars, respectively. The 100% Ep treatment showed the lowest irrigation water use efficiency (IWUE) (16.7 and 10.4 kg m 73 ), while 50% Ep showed the maximum IWUE (23.9 and 17 kg m 73 ) for TY-DANA and GS12 cultivars, respectively. The average fruit weight for 100% Ep treatment was usually higher than the other treatments. Generally, yield decreased using 50% Ep, however, the benefits of increasing IWUE and saving around 50% of irrigation water will help to grow crops in more areas and in managing the limited water resources in arid environments.