Observations were made on the development, mortality and fecundity of the gregarious endoparasitoid, Cotesia chilonis (Matsumura), when reared on four African stemborers, Chilo partellus (Swinhoe), C. orichalcociliellus Strand, Sesamia calamistis Hampson and Busseola fusca (Fuller). C. chilonsis accepted the four stemborers for oviposition, but parasitoid eggs were encapsulated in B. fusca. The percentage of C. partellus, C. orichalcociliellus and S. calamistis successfully parasitized was not different, and ranged from 65.4% to 73.4%. The mortality of parasitoid larvae was higher and immature development took longer in C. orichalcociliellus compared with S. calamistis or C. partellus. The numbers of ovarian eggs in adult C. chilonis females reared from C. partellus, C. orichalcociliellus and S. calamistis were 125.3, 79.5 and 120.6 respectively. none