The total lipid level of the digestive gland-gonad complex of Biomphalaria glabrata was reduced by starvation and elevated following infection with Schistosoma mansoni. 2. The lipid classes of B. glabrata were phospholipid, monoglyceride, free fatty acid, triglyceride, sterol ester and wax and a single unidentified lipid. The major lipid present in control, starved and infected tissue was sterol. Triglyceride was a minor component of control tissue. 3. Starvation reduced the relative level of the unidentified lipid but had little effect on triglyceride. 4. Infection also caused a decrease in the unidentified component but the triglyceride level was sharply elevated. 5. The phospholipid fraction of tissue from all groups was composed of phosphatidyl choline, phosphatidyl ethanolamine and phosphatidyl serine. Infection and starvation had little effect on the composition.