Cutaneous malignant melanoma accounts for 5% of cancer diagnoses and is the fifth most common cancer diagnosed in the United States. Risk factors for cutaneous malignant melanoma include ultraviolet radiation from sun exposure, Fitzpatrick skin type I or II, a history of dysplastic nevi, indoor tanning, older age, and a personal or family history of melanoma. The U.S. Preventive Services Task Force recommends counseling with patient education on minimizing early ultraviolet radiation exposure, including the use of protective clothing and sunscreen, especially for patients 6 months to 24 years of age. Tools to aid in the diagnosis of cutaneous malignant melanoma and the decision to biopsy include the ABCDE mnemonic, ugly duckling sign, and dermoscopy. Any suspicious pigmented lesion should be biopsied. Biopsy with a deep scoop shave, saucerization, punch biopsy, or full-thickness excision is preferred to ensure the entire lesion is removed to obtain an accurate measurement of Breslow depth. Breslow depth is important in staging, treatment consideration, and prognosis. Wide local excision by a dermatologist or surgeon with appropriate margins is the primary treatment of choice. Thin lesions with a Breslow depth of less than 0.8 mm usually do not need further treatment after wide local excision and have an excellent prognosis. Lesions with a Breslow depth greater than 0.8 mm may need further diagnostic tests or procedures, including sentinel lymph node biopsy, complete lymph node dissection, gene mutation analysis, and possible treatment with systemic immunotherapy. Use of systemic immunotherapies has improved the prognosis for advanced melanoma (stages III and IV), with 5-year survival rates of 74.8% and 35%, respectively, compared with 62.6% and 16% from 1975 to 2011 before immunotherapy was available.