Experimentation with alcohol constitutes a problem on the increase among young people in recent years, and mean age at first consumption has fallen. The goal of the present work was to carry out an exploratory study of attitudes toward alcohol use in terms of three dimensions (cognitive, affective and behavioural) in a sample of 755 secondary school pupils from the Principality of Asturias (Spain). Subsequently, we selected a sample of 141 adolescents described as at risk in view of their more permissive attitudes in relation to their lower age level (mean= 14.24 years), with the aim of applying a socio-educational preventive programme that included follow-up assessments at two, seven and twelve months. The results showed the preventive efficacy of the didactic activities programmed, a strengthening of attitudes contrary to experimentation with alcohol, and greater resistance to peer pressure, as well as the modification of patterns and frequency of use. Of the four programs applied (Family Intervention, Expert, Information, and Basic Sensitization), we found greater preventive efficacy for the competence-enhancement and psychosocial intervention programs, compared to the merely informational type.