Ultraviolet (UV)-associated cancer is the most common cancer in the United States. Approximately 90% of nonmelanoma skin cancer and 65% of melanoma are attributable to UV exposure and theoretically could be eliminated by primary prevention measures. Safe sun strategy includes use of sunscreens, use of protective clothing, minimization of exposure from 10 A.M. to 3 P.M., and avoidance of tanning parlors. Although more definitive data in human populations on the effectiveness of sunscreens to prevent melanoma and skin cancer are needed, sunscreens are thought to reduce risk. Safe sun prevention must start in childhood and adolescence when people receive most of their UV exposure. Secondary prevention through professional and public education and early detection may further reduce melanoma mortality.