Basal cell carcinoma is the most common form of skin cancer and usually occurs in the head and neck region. Most basal cell carcinomas grow slowly and behave in a relatively benign, nonaggressive fashion, but a proportion of them grow rapidly and infiltrate the structures beneath the skin. The dental surgeon may well come across this tumour and is in an ideal situation to recognize it. The aim of this article is to describe the clinical features of this common skin tumour and to provide a differential diagnosis. Early recognition of a basal cell carcinoma by the dental practitioner means that the patient can be referred for a specialist opinion and the tumour treated while it is still small.