We present the case of a 51-year-old woman suffering from septic arthritis of a lumbar facet joint, which was probably caused by an infected central venous catheter. Increased uptake on the bone scintigraphy was an early finding. Magnetic resonance imaging (MRI) of the spine contributed to the diagnosis by showing lesions of the facet joint and involvement of the surrounding soft tissues. Percutaneous needle aspiration guided by computed tomography established a bacteriological diagnosis. The positive response to antibiotic therapy was confirmed by MRI.