In the present study, we examined a bidimensional model of acculturation (which includes both heritage and U.S. practices, values, and identifications) in relation to hazardous alcohol use, illicit drug use, unsafe sexual behavior, and impaired driving. A sample of 3,251 first- and second-generation immigrant students from 30 U.S. colleges and universities completed measures of behavioral acculturation; cultural values (individualism, collectivism, and self-construal); ethnic and U.S. identity; and patterns of alcohol and drug use, engagement in potentially unsafe sexual activities, and driving while (or riding with a driver who was) intoxicated. Results indicate that heritage practices and collectivist values were generally protective against health risk behaviors, with collectivist values most strongly and consistently protective. Nonetheless, heritage identifications were positively associated with sexual risk taking for Hispanics. U.S. practices, values, and identifications were not consistently related to risk behavior participation. Results are discussed in terms of bidimensional approaches to acculturation, the immigrant paradox, and implications for counseling practice. (Contains 1 figure, 4 tables, and 1 footnote.)