The comparative efficiency for different infecting routes in experimental schistosomiasis in Swiss albino mice has been studied. Thirty mice, both male and female, two months old, have been each infected with one humdred Schistosoma mansoni cercariae, and sacrificed three months later. The following infecting routes have been used: oral, percutaneous (partial body submersion, tail imersion and dropping of water containg cercariae on a shaved area of the anterior abdominal wall), and intra-peritoneal routes. Per-cutaneous route (partial submersion of the body) proved to be the best and the highest mortality occurred in animais intra-peritoneally infected.