Melanoma is a malignancy that develops from the pigment-containing cells, the melanocytes. Melanoma represents 4% of skin cancers but causes 80% of skin cancer deaths. The various risk factors for melanoma are congenital nevi, common nevi, and atypical/dysplastic nevi. The environmental factors include ultraviolet radiation from natural and artificial sources. Genetic factors include high-risk/familial melanoma genes. Melanoma is classified into four clinical subtypes: superficial spreading malignant melanoma, lentigo maligna melanoma, nodular melanoma, and acral lentiginous melanoma. Melanomas rarely recur locally at the site of excision. They often recur as metastases at distant sites. Metastases cause the vast majority of morbidity and mortality in melanoma. Metastasis to visceral sites predicts poor outcome. Suspicious skin and subcutaneous lesions should be biopsied. A sentinel node biopsy is sometimes performed after a primary melanoma is diagnosed. Fine needle aspiration or core biopsy of the lymph node lesion usually is adequate for tissue diagnosis. Primary melanomas are typically treated with surgical excision. Approaches to metastatic melanoma include surgical metastasectomy, immunotherapy, targeted inhibition of the mitogen-activated protein kinase pathway, and radiation therapy. Newer therapies are vemurafenib, a BRAF kinase inhibitor, dabrafenib, and nivolumab.