We report a case of secondary psoas abscess in a 37-year-old man with a 3-week history of severe low backache managed conservatively without surgical drainage. Apart from bilaterally restricted straight leg raising (<70 degrees), his neurologic examination was within normal limits. Magnetic resonance imaging showed discitis of the L3-L4 space and a left-sided secondary psoas abscess. Aspiration biopsy of the abscess material under radiologic control isolated Staphylococcus aureus, which responded to appropriate antibiotic therapy with complete resolution. A high index of suspicion is necessary for diagnosis of psoas abscess, which should be considered in patients with pyrexia and backache with a neurologic examination that is otherwise normal. We discuss the recommendations for surgical and nonsurgical approaches.