Abstract: The bruchid Callosobruchus maculatus is the major constrain in cowpea production and storage in Algeria. Damage due to this insect affects especially the quality, the quantity and agronomic value of the product. In storage C. maculatus is currently parasitized by two parasitoids Anisopteromalus calandrae and Lariophagus distinguendus. The aims of this study were to evaluate the impact of the two parasitoids used alone or simultaneously and at different density on the reduction of emergence of C. maculatus bruchids adult’s. The effect of intra and interspecific competition between parasitoids was also studied. The results show that A. calandrae was much more efficient at reducing of emergence of C. maculatus (32.85%) than was L. distinguendus (42.92%). Competition reduced emergence of both A. calandrae and L. distinguendus; however A. calandrae was clearly the dominant species when bruchids were exposed to equal number of both species of parasitoids.