In order to study the effect of irrigation (I 0 : optimum irrigation I V and I R : water stress during vegetative and reproductive stages respectively) and nitrogen (N 1 : 25% at planting 50% at eight-leaf stage and 25% at head appearance; N 2 : 50% at eight leaf stage and 50% at head appearance; N3: 50% planting and 50% head appearance) on yield and growth of sunflower a split-plot experiment was conducted in 2011 and 2012. Average cross years IV and IR caused a significant reduction of final dry leaf (20.4 and 34.5%) stem (40.5 and 45.7%) and total weight (25.9 and 28.0%) and also a significant reduction of the grain yield as much as 14.8% and 13.3% in comparison to I 0 . N 1 caused a significant 25 and 14% reduction of the leaf area index in comparison to N 3 and N 2 ; however the grain yield was not significantly different in N 3 and N 2 in both years. In I 0 N 3 caused a significant 34.8% increase of final dry weight of the leaf and an insignificant increase of dry weight of stem and the total weight as much as 30.9% and 16.3% respectively and also a significant 16.4% reduction of the grain yield in comparison to N 2 . On the whole N2 treatment in different irrigation regime caused a higher grain yield in comparison to N 1 and N 3 but N 3 treatment in I 0 and N 1 in I V and I R reduced the grain yield.