About one of every six high school seniors and dropouts averaged at least one alcoholic drink every other day. More than 25 percent experienced a drinking-related problem, such as missing school and feeling sick, on at least three occasions during the previous year. The same proportion engaged in two or more high-risk drinking activities, such as combining alcohol with other drugs and getting drunk, on multiple occasions during the previous year. Two lessons are drawn from the findings: (1) different definitions of alcohol misuse result in widely different estimates; and (2) various measures confirm teenage alcohol misuse is a significant problem. The pervasiveness of teenage alcohol misuse is examined in relation to the association between teenage drinking and accidents, suicide, violent behavior, high-risk sex, and emotional problems. The DPRC recommends that efforts to reduce the undesirable effects of teenage alcohol misuse take into account the prevalence of alcohol misuse among teenagers and its social context. 1 figure