The sample is made up of 1,190 adolescents (52.8% boys; mean age = 16.81) from 37 random schools in the urban and rural areas of Asturias (northern Spain). The survey was conducted in 2008, assessing the use and patterns of use of alcohol and other drugs, age at onset of use, and psychosocial consequences. Items from the ESPAD and FRIDA questionnaires were employed. Univariate analyses and binary logistic regression analyses were carried out to determine the different predictive value for boys and girls of early-onset alcohol and tobacco use. The study's limitations and implications are noted.