In sixty-sight patients with Schistosomiasis mansoni (hepato - splenic form), the Author stuãied the comparative value of rectal biopsy (six or nine mucosal snips) and the stools examinations by Hoffman, Pons & Janer method. The Author conclued that the stool ezamination in the patients with splenomegaly (hepato - splenic form of Schistomiasis mansoni) proved superior (76.47% of the cases) than multiple rectal biopsy (32.35% of the cases) for the demonstration of viable eggs of Schistosoma mansoni.