BACKGROUND Thrombotic thrombocytopenic purpura (TTP) is a life-threatening but treatable disorder. Acute pancreatitis is a well-described consequence of TTP, but TTP as a consequence of acute pancreatitis is rare. METHODS A 32-year-old male developed acute pancreatitis due to a fatty diet and suffered splenectomy 3 years ago due to trauma. From day 4 of his onset of pain the blood examination showed the platelet extremely reduced, bilirubin elevated and creatinine increased. High clinical suspicion of TTP was made and prompt initiation of plasma exchange was given followed intravenous drip methylprednisolone. After 7 sessions of plasm exchange and the laboratory parameters were back to normal and the patient was discharged from the hospital on the 13th day of admission. CONCLUSIONS Patients develop acute pancreatitis with no apparent causes for hemolytic anemia and thrombocytopenia, the possibility of TTP should be considered. Treatments for TTP including plasm exchange should be evaluated as soon as a diagnosis is made.