Basal cell carcinoma (BCC) is a malignant epithelial neoplasm of the skin preferentially affecting male caucasians and is rarely observed in patients with more intense skin pigmentation. A characteristic feature of BCCs are their extremely low risk to metastasize. Epidemiological data indicate that the overall incidence is increasing worldwide significantly by about 3-10% per annum.(1-3) Based on the increasing incidence of this usually not life-threatening tumour BCC appears to develop into a growing public health problem. This review elucidates the risk factors for the development and for the progression of BCC leading to an improved understanding of this tumour.