The results of this investigation show that the hamsters (Cricetus auratus) may be used as an experimental model for immunological studies in Schistosoma mansoni. The data obtained referring to concomitant immunity, production of lethal antibodies and immunosuppression, resemble data from other established experimental models. Our observations indicate that the hamster has the following advantages: 1. It is an appropriate host for the maintenance of S. mansoni in the laboratory. 2. It can be considered an alternative model for easy growth and maintenance of this parasite. 3. It is easy to handle.