Iliopsoas abscess is an uncommonly encountered clinical entity. Although diseases of the digestive tract or urinary tract or trauma can secondarily cause an iliopsoas abscess, the number of "idiopathic" or "primary" cases of iliopsoas abscess has been increasing since the later twentieth century. Unlike the intraperitoneal tissues, those of the extraperitoneum may demonstrate little visible reaction to bacterial contamination. Thus prolonged illness and high mortality rate due to delay in diagnosis or inadequate treatments are common. We present a case of iliopsoas abscess with a history of Child’s class C liver cirrhosis. After fever and abdominal distention with progressive abdominal pain over left lower quadrant were noted, CT scan revealed a multiloculated abscess over the left retroperitoneum. After aggressive treatment with antibiotic therapy, surgical drainage and intensive care,
the patient recovered and was discharged.