The Present study was conducted over a 13 year period to study grain yield and yield related traits responses to regulated deficit irrigation, applied throughout the crop cycle, at jointing and heading growth stages, compared to a rainfed check in durum wheat (Triticum durum Desf.). The results showed that the measured traits responded to applied water and the response was dependent on seasons, levels of regulated deficit irrigation and crop growth stage at which water was applied. Grain yield increase was correlated linearly to water use efficiency and curvi-linearly to total water evapotranspired. Water application at jointing gave a more variable and significantly low grain yield increase compared to grain yield increase observed when limited irrigation was applied at heading. Yield reductions from maximum yield obtained under rainfed conditions were positively correlated with the accumulated rainfall of the October-February period. In environment like the high plateaus of eastern Algeria where water resources are scare, the results of this experiment suggested that limited irrigation applied at heading stage increase effectively grain yield and reduces from the risk of crop failure.