PURPOSE: An Incidence of primary iliopsoas abscess is extremely rare. So it's clinical features are unclear. We reported the clinical features and treatment of primary iliopsoas abscess with reference review. METHODS: The ten cases of primary iliopsoas abscess from January 1999 to August 2003 were included in this study. We analyzed clinical manifestation, diagnostic modality, treatment and prognosis retrospectively. Microbiologic study and imaging study were performed in all patients. The treatments included surgical drainage, percutaneous drainage, and systemic antibiotics only were performed. RESULTS: In demographics of patient, the sex ratio was equal and mean age was 51.8 years old with predominant elderly (more than 60 years old). The abscess was confirmed by computed tomography in 8 patients, magnetic resonance imaging in 1. One abscess was found after laparotomy. The one side iliopsoas abscess was found in eight cases (right 4 cases and left 4) and bilateral abscess was in two cases. All cases were multilobulated abscess. After failure of percutaneous drainage, surgical drainage with retroperitoneal approach was performed in 8 patients. Transperitoneal drainage and systemic antibiotics therapy without drainage was respectively performed in one case. One case of abscess was recurred due to early removal of drain and insufficient antibiotics therapy. Other nine patients were completely resolved without complication or mortality. CONCLUSION: The diagnosis of primary iliopsoas abscess requires a high index of suspicion due to its rarity. If we consider that most iliopsoas abscess was multi-lobulated, early surgical drainage with sufficient administration of systemic antibiotics is an effective treatment modality.