A 29-year-old man with complaints of pain in the low back, both flanks, and midepigastrium was found to have vertebral osteomyelitis. Mediastinal abscess was also diagnosed on the basis of findings on chest x-ray film, thoracic ultrasonography, thoracentesis, and cultures of pleural fluid. Antibiotic therapy was begun, and open drainage with rib resection was performed. After six weeks of treatment, the patient was free of symptoms. We believe this is the first report of mediastinal abscess secondary to vertebral osteomyelitis in an adult since the advent of antibiotics.