Hemolytic uremic syndrome (HUS) is defined by the triad of renal failure, thrombocytopenia and hemolytic anemia. HUS is usually developed by infectious disease in children, but occasionally in adults. Infectious disease associated with HUS is characterized by fever and diarrhea-commonly related with Escherichia coli O157:H7. Verotoxin (Shiga-like toxin) produced by E. coli damage the endothelial cells, promote local thrombosis and finally step to HUS. Other causes of HUS include drugs, pregnancy, organ transplantation and malignant tumor. We report two adult patients cases of HUS associated with infectious diarrhea.