While rates of HIV and STD infection in Eastern Europe are increasing rapidly, little is known about sexual behaviour, including condom use, among Eastern European youths. The Study of Hungarian Adolescent Risk Behaviours was designed to assess the knowledge, attitudes, and behaviours of adolescents studying in secondary schools in Budapest, Hungary. Students (n =3486) in a random sample of public secondary schools completed a self-administered questionnaire, including measures of sexual activity and condom use. Thirty-eight percent of students reported ever having had vaginal intercourse. Condom use by those reporting having had sex in the past five weeks was classified as consistent/every time (40%); irregular (25.6%); and none (34.3%). Multivariate analysis revealed positive opinions about condoms, fear of AIDS, and initiation of condom use by both partners to predict more frequent condom use. Implications for targeted AIDS/STD education and prevention among adolescents are discussed.