Melanoma is an increasingly common malignancy, and it affects a younger population than most cancers. Risk factors for melanoma include white race, sun sensitivity, family history of melanoma, and melanocytic nevi. Sunburn and intermittent sun exposure appear to increase the risk of developing melanoma. The role of population-based screening for skin cancer remains unclear. Consistent screening results in the diagnosis of thinner melanomas, but there is no evidence that this leads to decreased mortality. The ABCDs--asymmetry, border, color, diameter--can be used as a guide to differentiate melanoma from benign lesions. Suspicious pigmented lesions should undergo full thickness biopsy. Treatment consists of surgical resection, lymph node evaluation, and systemic therapy for some patients. Prognosis depends on the stage at diagnosis. Patients with melanoma require dose follow-up because they are at risk for recurrence and diagnosis of a second primary tumor. Preventive strategies for melanoma should emphasize seeking shade when outdoors, wearing protective clothing, and avoiding exposure during the peak sunlight hours.