Abstract The absence of appropriate animal models is a challenge for those designing anti-schistosome vaccines. In order to observe the development of hepatic granulomata, 20 Krad irradiated cercaria vaccinated grivet monkeys ( Cercopithecus aethiops aethiops) were experimentally infected with Schistosoma mansoni. Most human clinical manifestations of schistosomiasis were noted in the infected monkeys. Intraperitonial immunization with 20 Krad irradiated cercaria resulted in a relatively less granulomatous reaction and lower egg mass ( P < 0.05) than in the controls. The mean total adult worms and egg production was also lower in the vaccinated group. This study underlines the significant role of irradiated cercariae vaccination on the establishment of female adults and consequent reduction of pathology in the grivet Cercopithecus aethiops aethiops.