Spinal epidural abscess is an uncommon, but a significant disease due to its high morbidity and mortality rate if not diagnosed in time. Although early diagnosis and prompt surgical intervention is needed for better prognosis of this disease, the diagnosis of spinal epidural abscess is often elusive despite modern medical advances, and depends on a high index of suspicion. we report a case of lumbar spinal epidural abscess of unknown origin complicated by cauda equina syndrome.