This chapter reviews the most common malignant cutaneous tumors. The section on malignant tumors of the epidermis discusses nonmelanoma skin cancer (i.e., basal cell carcinoma and squamous cell carcinoma) and malignant melanoma. The section on malignant tumors of the dermis covers metastatic tumors, primary tumors (Merkel cell carcinoma, Paget disease, extramammary Paget disease, angiosarcoma, and dermatofibrosarcoma protuberans), and Kaposi sarcoma (i.e., classic Kaposi sarcoma, African Kaposi sarcoma, organ-transplant Kaposi sarcoma, and HIV-associated Kaposi sarcoma). The final section covers cutaneous lymphomas. The coverage of each disease includes a discussion of epidemiology, etiology, diagnosis, differential diagnosis, treatment, and prognosis. Tables provide the adjusted estimated relative risks of melanoma by nevus type and number, the American Joint Committee on Cancer (AJCC) TNM classification and staging system, the estimated probability of 10-year survival in patients with primary cutaneous melanoma, and an overview of overview of therapy for cutaneous T cell lymphoma. Figures illustrate the presentation of many malignant cutaneous tumors. This review contains 10 highly rendered figures, 5 tables, and 105 references.