Chilli pepper, Capsicum frutescens (L.) (whole and powder) was evaluated for their insecticidal activities against the bruchid, Callosobruchus maculatus to prevent loss of cowpea in storage. There were eight treatments (1.0g, 2.0g and 3.0g of chilli pepper powder, 1.0g, 2.0g and 3.0g of whole fruit of chilli pepper, actellic dust 2% and no protectant control) in five replications laid-out in complete randomized design. 200g of cowpea seeds were admixed with each of the treatments for their efficacy against oviposition, damage and weight loss to Callosobruchus maculatus. Percentage germination and proximate composition were also tested after storing seeds for periods ranging between 38 days and 4 months. Results revealed that chilli pepper powder and whole fruits at all levels reduced to its barest minimum the number of eggs laid or hatched by Callosobruchus maculatus preventing adult emergence and survival at 38 days after infestation, weight loss after 4 months and increased percentage germination as compared to control (60.0±0.0 and 40.0±0.0). Chilli pepper had significant influence on proximate composition as treated cowpea retained their nutrient after four months of storage. 3.0g chilli pepper powder was observed to be very effective than other treatments and control.