A trial was conducted during the 1991 cotton growing season to evaluate sidedress applications of aldicarb for cotton aphid control. All aldicarb treatments significantly controlled cotton aphid populations and reduced defoliation on late planted cotton. Detailed plant mapping data collected from select treatments indicated that aldicarb at 1.0 lb ai/a significantly increased the number of first position bolls from nodes 5-10. This same treatment also significantly increased lint and seed weights and fiber length/first position bolls at nodes 5-6. Aldicarb at 1.0 lb ai/a had limited effect on fiber strength but any significant changes were positive. There were no differences in micronaire between treatments. The number of fruitless plants/row ft was significantly decreased in the aldicarb treatment and yield was significantly increased over the untreated check.