The diversity of symbionts associated with insects and the range of effects they exert on their hosts have prompted studies to understand the role these microorganisms may have on host biology, particularly in relation to the interaction of their hosts with other trophic levels. There is also a possibility of using such symbionts as vectors of genes for insect control or learning on the mechanisms they use to interact with their hosts for the development of new approaches to insect control. Since most of these symbionts are transmitted transovarially from one generation to another, we used electron microscopy to assess the occurrence and morphology of these microorganisms in the female reproductive tissues of two important insect pest parasitoids, the braconids Cotesia flavipes and Doryctobracon areolatus. Cotesia flavipes was associated with a polydnavirus (PDV), whereas D. areolatus harbored the rickettsia-like bacterium Wolbachia. The ultrastructural morphology and localization of these symbionts in their host ovaries are described. None of the populations of the species studied were associated with non-PDV particles, and their sole association with specific symbionts will facilitate studies on the role of these symbionts in the association with their hosts, and on the associations of their hosts with other trophic levels.