We report our clinical experience with three patients in whom squamous cell carcinomas developed secondarily to chronic bone infections. The diagnosis was delayed in each case.

There are several well recognised warning signs which should alert the physician to the possibility of malignant change having occurred in the region of chronic bony infection.

Close attention to these signs will prevent undue delay in diagnosis and avoid the associated complications.

As chronic osteomyelitis becomes less common in first world countries we need to remain aware of the possible complications which can be encountered.

The diagnosis in each of our cases was delayed by the fact that the possibility of malignant change was not considered by several experienced orthopaedic surgeons.

When there is change in signs and symptoms or altered flora within the discharge one must be alerted to the possibility of malignant change. This should prevent delays in diagnosis. Radiological progression should probably be regarded as malignant change until proven otherwise.

With early diagnosis and treatment the prognosis for a patient with squamous cell carcinoma is good. Key words: Osteoclastoma, Osteomyelitis, Sinus tract, Squamous cell carcinoma.