Field experiments were conducted at two locations in 1989 and 1990 to investigate possible interactions between POST applications of primisulfuron and selected soil-applied carbamate and organophosphate corn insecticides. Insecticides were applied in-furrow at planting, at recommended use rates. Primisulfuron was applied POST to corn in the three- or five-leaf stage at 0, 20, 40, or 80 g ai ha-1. Combinations of primisulfuron with disulfoton, fonofos, isozophos, or terbufos resulted in foliar and root injury, plant height reductions, and yield losses. No foliar or root injury, plant height reductions, or yield losses were observed from combinations of primisulfuron and carbaryl, carbofuran, chlorpyrifos, or diazinon. Differences among and within the experiments are attributed to edaphic and environmental conditions at the time of primisulfuron application.