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As regards to the high volume of imports of vegetable oil in the country and limited water resources, recognition factors affecting on crops production in low water conditions is very important. In order to investigate the effect of chitosan foliar application in deficit irrigation conditions on quantitative and qualitative characteristics of sunflower Alster cultivar, this experiment as split plots on the basis of randomized complete blocks design with three replications was conducted at the research field of Zabol Agriculture college in 2011-12 cropping year. The factors of experiment included drought tension in three levels watering based on 25 percent of available moisture (sever tension), 50 percent of available moisture (mild tension) and 75 percent of available moisture (control) as the main factor and chitosan foliar application at three levels: zero (control), two gram in liter and five gram in liter as sub factor. In this experiment drought tension caused reduction in plant height, one-thousand grain weight, biological yield, grain yield, harvest index, chlorophyll a, chlorophyll b, total chlorophyll, head diameter, but no significant effect was observed on harvest index and oil percentage. Also, foliar application of chitosan leaded to increasing plant height, one-thousand grain weight, biological yield, grain yield, head diameter and total chlorophyll.