A 76-year-old male was admitted to our hospital with complaints of lumbago and difficulty in movement. He had a two-year history of rheumatoid arthritis, treated with a combination of methotrexate and tocilizumab. His chest-abdominal computed tomography image demonstrated the destruction and compression of thoracolumbar vertebral bodies and right-sided pleural effusion. The right-sided pleural effusion was diagnosed as empyema due to methicillin-sensitive Staphylococcus aureus by bacterial analysis. T2-weighted spinal magnetic resonance imaging demonstrated an increased signal intensity at the level of Th12-L1, suggesting vertebral osteomyelitis. Antibiotics and tube drainage failed to cure the right-sided pleural empyema and vertebral osteomyelitis and the patient died. An autopsy revealed that vertebral osteomyelitis had caused the right-sided pleural empyema. This case suggests that exudative pleural effusion/empyema can be an unusual consequence of pyogenic vertebral osteomyelitis in immunocompromised patients with back pain.