Field experiment was conducted at the farm of Faculty of Agriculture, GomalUniversity, Dera Ismail Khan to determine integrated effect of nitrogenous fertilizer and syntheticinsecticides on aphid, Lipaphis erysimi (Kaltenbach) (Homoptera: Aphididae) population in canolacrop during 2010-11. Results showed that tested insecticides significantly reduced aphid populationcompared to control. Minimum (8.67aphids) were recorded after 3rd week of treatment with karate 2.5EC (625ml.ha-1) using medium dose (58kg.ha-1) of nitrogen fertilizer. The same treatment also provided maximum (1246.91kg.ha1) grains yield. It was concluded from the present studies that testedlevels of nitrogen fertilizer had no effect on aphid population, while synthetic insecticides significantlyreduced pest infestation.