A case is presented of a 40-year-old man with rapidly progressing symptoms of thoracic medullary compression, initially thought to be caused by metastatic pulmonary malignancy. Further investigations, however, revealed thoracic actinomycosis spreading to the vertebral column and an actinomycotic epidural granuloma was causing medullary compression. After decompression by laminectomy and antibiotic treatment with penicillin there was some neurological improvement. The condition is rare, and some of the diagnostic difficulties are discussed.