Squamous cell carcinoma arising in a skin graft is rare. Previous reports concern the use of skin in heterotopic locations namely the vagina and oral cavity. We report a case of squamous cell carcinoma, which arose in a skin graft used for resurfacing a scalp defect. The defect followed the excision of a basal cell carcinoma 11 years previously. The excision was incomplete and radiotherapy had been given. The possible pathological mechanisms for the development of a squamous cell carcinoma in transplanted skin are discussed.