Learning Objectives: After studying this article, the participant should be able to: 1. Describe the epidemiology and etiology of basal cell carcinomas. 2. Understand the biology, histogenesis, predisposing conditions, and syndromes associated with basal cell carcinomas. 3. Have a clear understanding of tumor types and their clinical behavior. 4. Discuss the importance of diagnostic tumor biopsy and treatment options as they pertain to anatomic site, tumor type, and patient age. 5. Understand the basis for surgical management of basal cell carcinomas, the margins of excision, indications for frozen section, and Mohs micrographic surgery. 6. Discuss the value of patient follow-up after treatment of a primary basal cell carcinoma. 7. Review the most recently published literature on this topic and understand new concepts in tumor biology as they relate to diagnosis and treatment options.Basal cell carcinoma is a malignant epithelial neoplasm of the skin that often arises in areas of chronic sun exposure. This article reviews the epidemiology, etiology, and treatment of basal cell carcinomas. Tumor biology is emphasized to provide a rational basis for specific treatment options.