The inoculation of Staphylococcus aureus into the tibial marrow cavity of rabbits following tibial fracture and rod insertion, as well as into the rodded tibia without fracture, results in chronic staphylococcal osteomyelitis in a high percentage of the animals. Staphylococci were easily recovered from the tibial marrow cavity for as long as eighteen months after onset of the infection. This model closely resembles the human disease in which chronic osteomyelitis develops as a complication of internal fixation devices, and provides a reliable method for evaluating various specific approaches to the treatment of this difficult problem in management.