A 31-year old Egyptian was referred to evaluate the etiology of elevated liver enzymes. The patient had been suffering from diabetes type 1 for three years and complained about episodes of light diarrhea. Laboratory investigation revealed a moderate elevation of cholestatic enzymes. Ultrasound examination and computed tomography did not show mechanical biliary obstruction. Drug-induced cholestasis, viral hepatitis and primary biliary cirrhosis could be excluded as well. Finally, schistosomiasis mansoni was diagnosed by microscopic stool examination as well as histological evaluation of biopsy specimens obtained during colonoscopy. This parasitic disease may cause slowly progressive liver injury by the release of schistosome eggs into the portal vein system. Histological evaluation of liver specimens of this patient showed portal inflammation and the presence of pigmented macrophages. This pattern, though unspecific, was consistent with the diagnosis of schistosomiasis mansoni. Treatment with praziquantel resulted in regression of diarrhea episodes and normalization of cholestatic enzymes within three months.