OBJECTIVE To find how much alcohol, tobacco and drugs adolescents consume and identify some linked socio-family variables. METHODS A crossover and descriptive study, with randomised sampling stratified by classrooms. METHODS Secondary schools in the town of Lugo. METHODS 805 students of both sexes from the secondary schools. RESULTS We used a self-filled anonymous semiclosed questionnaire. 34.6% habitually consumed alcohol, of whom 43.3% had got drunk at least once in the previous 6 months and 7.1% on more than 13 occasions. 25.7% were habitual smokers. 12.3% had consumed cannabis; 10.1% tranquilisers; 7.5% amphetamines; 4.6% sleeping pills; 2.1% cocaine; 1.9% LSD; 1.5% heroin. Variables linked to consumption were: age, repeating the school year, considering him/herself a bad student, fighting, consumption by both parents, not doing sports, having more money and not having a good relationship with parents. CONCLUSIONS Adolescent alcohol, tobacco and drug consumption is high and similar to other regions of Spain. Prevention strategies are needed, in the family, at school and in the media.