We present the case of a young man with chronic Actinomyces naeslundii infection in the lower leg who underwent a below-the-knee amputation after unsuccessful attempts at diagnosing and eradicating the infection. Actinomycetic organisms from environmental sources can engender a dense fibrotic tissue response without fistulae. Such a response led to a painful, sclerosing, nonsuppurative infection of the bone and surrounding tissues in our patient. This clinical picture, at least the bony and periosteal reaction, was compatible with Garrè's osteomyelitis.