A 46-year-old man presented with fever, thrombocytopenia, and a considerable accumulation of ascites. Although prednisolone and intravenous cyclophosphamide pulse (IVCY) were effective, he experienced recurrence. Renal insufficiency and hemolytic anemia developed subsequently. Schistocytes, negative Coombs' test, and elevated lactate dehydrogenase levels indicated thrombotic microangiopathy (TMA). He recovered well after receiving plasma infusion, IVCY, and prednisolone. Renal biopsy revealed subendothelial widening, thereby confirming TMA. This is a very rare case of TMA that presented with a considerable volume of ascites.