To study the effect of 20,000, 30,000, 40,000, and 50,000 plants per hectare and 0, 55, 110 and 165 kg per hactare of diammonium phosphate (DAP) on sunflower yield, an experiment was conducted on hybrid I-S 894 on fallow land and in standing sugarcane crop at the Malakandher Farm of the NWFP. Agricultural University, Peshawar during the year 1981. Sunflower grain and stalk yields increased with increase in the rate of DAP application. Grain yield increased with increase in plant population in the experiment on fallow land but decreased in the sugarcane crop. The lowest population of sunflower in combination with the highest rate of DAP had no adverse effect on the yield of sugar-cane crop.