The efficacy of oil extracted from the leaves of Secamone afzelii was evaluated in the laboratory against Callosobruchusmaculatus infesting stored cowpea. Leaf extracts from S. afzelii were obtained through the soxhlet extraction method usingmethanol and hexane as the solvent. Each of the extracts was tested by exposing five pairs of adult beetles to various levelsof 0.5, 1.0, 1.5 and 2.0 ml corresponding to 2.5, 5.0, 7.5 and 10.0% v/w concentrations admixed with 20g cowpea in threereplications respectively, in a Completely Randomized Design (CRD). Control treatment was set along. The results showedthat oviposition and percentage egg hatched were significantly (P <0.05) suppressed on seeds treated with higher treatmentlevel of extracts. Leaf extract with hexane at 2 ml (10.0% v/w)/20g cowpea seeds was most effective in suppressingoviposition and egg hatched. Therefore, S. afzelii exhibit promising degree of oviposition deterrent and ovicidal propertiesand, thus, have a great potential for use as a plant-based biopesticide as an alternative to synthetic insecticides forcontrolling C. maculatus infestation on stored cowpea grains.