Abstract: Chickpea (Cicer arietinum L.), an important food legume grown in the arid and semi-arid tropical regions, suffers substantial yields loss due to water deficit at the end of the growing season. The main objective of this study was to investigate the effect of gradual water deficit stress on grain protein and grain yield of desi and kabuli chickpea cultivars. Two field experiments were carried out in 2007 and 2008, to evaluate responses of three chickpea cultivars (Hashem and Arman from kabuli and Pirooz from desi type) under well watering (I1: 70 mm evaporation from class A pan), gradual water deficit (I2 and I3: 70→90→110→130 and 70→100→130 mm evaporation, respectively) and water stress (I4: 130 mm evaporation). As water deficit increased, percent of grain protein also slightly increased although this increasing was not significant. By applying water deficit, grain and biological yield were decreased. This reduction was significant under gradual water stress (I2 and I3) and well watering (I1), compared with water deficit (I4). Grain filling period under I4 was 16 and 9 days shorter than I1 and gradual water stress treatments (I2 and I3), respectively, leading to the most reduction in grain yield. There were no significant differences in grain and biological yield among I1, I2 and I3 irrigation treatments. Progressively increasing irrigation intervals (I2 and I3 irrigation treatments) can help the chickpea plants to adopt water stress and prevent significant reductions in grain and biological yield per unit area. Arman is a superior cultivar under both well watering and limited irrigation conditions.