To evaluate the effect of improvers and water deficit on seed yield and irrigation water use efficiency of sunflower (Helianthus annuus L.), a field experiment was conducted as split-factorial in randomized complete block design with three replications in Isfahan and Tehran, Iran, during the 2012 growing season. Experimental treatments were 1- water stress at three levels 60, 120 and 180 mm evaporation form class A pan were assigned to main plots, 2- soil improvers at three levels control (no application), zeolite (4.5 t.ha-1) and super absorbent polymer (100 kg.ha-1) and 3- plant improvers at theree levels control (zero), calcium silicate (400 mg.l-1) and Hexaconazole (2 g.l-1) as factorial were randomized in sub-plots. Water deficit significantly decreased seed yield (45%) and oil yield (20%), biological yield (22%), seed number per plant (32%) and 1000 seed weight (29%). Application of zeolite and hexaconazole led to higher seed yield. Water deficit at 180 mm level reduced the oil yield by 58%. Application of super absorbent polymer and calcium silicate reduced the effect of water deficit stress by 19%. Application of zeolites and hexaconazole had the highest irrigation water use efficiency (IWUE). IWUE increased with application of combination of soil and plant improverby 25% to 59%.