Different N sources, i.e. urea formaldehyd (UF), ammonium sul-phate (AS), ammonioum nitrate (AN) and urea (U) at the rate of 105 kg/N under two insecticides, i.e. aldicarb and diazinon were evalulated on corn in a pot experiment (25 Kg capacity) as well as their residual ef-fect on flax as a subsequent winter crop. Results showed that the dry weight of stem, leaves and ear leaf as well as straw yield/plant were insignificantly affected by either N source or insecticide, while, ear weight and grain yield/plant were signifi-cantly affected. The superiority of N sources for ear weight and grain yield/plant was in the order : UF >AS>AN>U. The interaction effects showed that using the insecticides under different N sources yielded more ear weight and grains than that of the control (without insecti-cides). N content of leaves, stems and grains were generally reduced by the insecticide application. Ear leaf analysis of N,P and K showed that AN was superior than the other N sources in association with diazinon which gave the highest values. Growth and yield of flax as a subsequent crop were insignificatnly affected by the residuals of the insecticides. Meanwhile, urea fertilizer was superior to other N sources with regard to the residual effect on flax yield. Application of the recommoded N rate (45 Kg N / fed.) gave higher values for flax growth and yield as well as N,P and K contents than those resulted from residual effect of either N or insecticides.