Background. The use of potentially addictive substances may be influenced by the young person's place of residence. Objective. To determine the frequency and characteristics of tobacco, alcohol and cannabis use in secondary school pupils in a small urban area during the academic year 2008-09. Methods. Cross-sectional survey. Socio-demographic data related to tobacco, alcohol and cannabis use were gathered by means of a confidential self-administered questionnaire. Results. The survey was responded to by 88% of the pupils (393). Prevalence of tobacco use was 48%, 16% of whom smoked every day. Forty four percent of third grade pupils and fifty two per cent of forth-graders, did consume alcohol on the week ends. Thirty-five percent said that they had been drunk on at least one occasion, while 30% of the pupils had tried cannabis, and 50% of third-graders. Among those who had used cannabis, 23% had done so in the previous month. At onset of cannabis use was 13 years. Almost 80% of those surveyed said they had not paid for the first drugs they used. Conclusions. The use of legal and illegal drugs for those in our sample begins between the ages of 12 and 14 years, representing slightly higher frequencies than those found in big cities. Despite the illegality of the sale of tobacco and alcohol to minors, Spanish teenagers continue to obtain them. It is essential for primary care professionals, educators and families to be aware of the importance of early detection of the use of psychoactive substances. The prevention of drug addiction is more effective the sooner the potential risk is detected.