A new animal model for posttraumatic osteomyelitis was designed. This model mimics the pathogenesis of the human disease more accurately than models presently available. Femora of New Zealand white rabbits were exposed at the greater trochanter and a stainless steel rod was inserted into the marrow cavity. A Staphylococcus aureus suspension was placed in and around a bone defect, which was drilled midshaft. The disease was evaluated by clinical observation and roentgenographic, hematologic, bacteriologic, and histologic parameters. Osteomyelitis developed in all 24 infected rabbits. None of the five rabbits receiving only an intramedullary rod developed an osteomyelitis. This model proves that an experimental posttraumatic osteomyelitis associated with a foreign body can be reliably induced, even when no infection-promoting chemical agents, small inoculum of bacteria, or minimal bone trauma is present.