Achromobacter xylosoxidans (A. xylosoxidans) has been described as an opportunistic pathogen causing infection. The case we describe is that of an elderly man who had osteomyelitis of calcaneal bone caused by A. xylosoxidans. As far as we are aware there are only 5 cases of osteomyelitis with A. xylosoxidans in the literature. Impaired defensive mechanism of the foot in direct contact with this waterborne bacterium can cause this disease. Because of the high level of antibiotic resistance of this bacterium, clinically more attention should be paid to patients who have impaired defensive mechanisms in their extremities, for example free flaps.