Three American ethnic subcultures, all consisting of transmigrated groups living in poverty, were studied and the sexual patterns of the youth described. The groups con sisted of white Appalachians living in Chicago, Negroes in Washington, D.C., and Puerto Ricans in New York. Sharply differentiated patterns of sexual behavior, involving conquest, sex education, sex misinformation, attitudes toward females, responsibility, and affect were discovered, and these patterns are reflected in the language of the subcultures, particularly in their argot. The underclass sexual mores differ from those of the American middle class, but not more than they differ from each other among the three ethnic groups. Sexual practices are related to general life styles, and reflect ghettoization, subcultural isolation, and short-range hedonism in groups only recently transplanted from their rural areas of origin.