Abstract: The effect of Baythroid (an insecticide) on dry matter yield and N yield of maize (Zea mays L.) was observed with particular emphasis on the uptake of N from soil and applied (15NH4)2SO4. Baythroid was applied @ of 0, 0.4, 0.8, 1.6, 3.2 and 6.4 mg kg-1 and N @ of 25 mg kg-1. The plants were harvested at two growth intervals i.e., 22 days and 47 days after sowing. At the two lower rates, Baythroid had no significant effect on dry matter yield of plants, while at the highest rate studied i.e., 6.4 mg kg-1, it had a negative effect. Maximum beneficial effect of Baythroid on dry matter yield and N uptake was observed at 3.2 mg kg-1. Trends in total plant N were similar to that for dry matter yield and a close correlation was observed between the two parameters. Baythroid application resulted in a significant increase in the uptake of both applied N and native soil N and the losses of applied N were substantially reduced.