Primary iliopsoas abscess is a rare but potentially serous condition. The diagnosis is frequently delayed due to its variable and nonspecific fcatures and occult clinical course. The delayed diagnosis and treatment of iliopsoas abscess is the major poor prognostic factor. We report a rare case of primary iliopsoas abscess that presented as a femoral neuropathy in a patient on hemodialysis. A 49-year-old man with end stage renal disease was admitted due to pain in the lft inguinal area, and weakness and hypoesthesia of left lower leg. Left iliopsoas abscess was confirmed by CT and MRI. Left femoral neuropathy was diagnosed with electrodiagnostic study. Iliopsoas abscess with femoral neuropathy was completely treated with CT-guided aspiration, antibiotics and prolonged physical therapy of hip and knee joints. To our knowledge, this is the first case report of primary iliopsoas abscess presented as a femoral neuropathy in a patient on hemodialysis in Korea. (Korean J nephrol 2004;23(1):180-184)