Broiler chicks were fed diets containing 0, 10, 20, 30, 40 or 50% sunflower seed (SFS) during the starter and finisher phases. Increase in dietary level of SFS above 20% caused a significant decrease in feed intake, weight gain and increase in feed conversion ratio (P<0.05) during the starter phase(0-4 weeks). During the finisher phase(5-8 weeks), birds fed with 50% SFS had a lower feed intake and weight gain compared to birds fed the other diets (P<0.05). Feedcost/kg weight gain were lower for birds fed diet with 40 or 50% SFS (P<0.05). However, there was no significant effect of the dietary level of SFS on mortality rate (P>0.05) both at the starter and finisher phases. Over the 8 week experimental period, increase in dietary level of SFS above 20% caused a decrease in feed intake , weight gain and feed conversion ratio (P<0.05). Dietary levels of SFS above 3 0% also reduced carcass and gizzard weight (P>0.05) but had no significant effect on other organs (P>0.05). It is concluded that broilers could tolerate up to 20% SFS without detrimental effect on performance.