Squamous cell carcinoma from the draining sinus of chronic osteomylitis has been recognized as a rare complication. The incidence of this complication is between 0.23% and 1.6% in cases of osteomyelitis. The cause of development of carcinoma at the site of chronic osteomyelitis is not well understood. This is a disease of middle aged men, and tibia is the most common site. Biopsy of squamous cell carcinoma which arises in the proliferating edge of the cutaneous ulcer and invades the bone, should include tissues from all sites of ulcer and bone marrow spaces. Histological diagnosis may be difficult because of preexisting metaplasia and pseudoepitheliomatous hyperplasia. Amputation at the adequate level is the treatment of choice. Four cases of squamous cell carcinoma involving tibia, metatarsal bone or calcaneus are reported with review of literatures.