Drug abuse is a public health world wide problem of, and Guanajuato’s University High School students are not exempt from this phenomenon. This study evaluated the prevalence in usage of several drugs, alcohol and tobacco, the associated psychosocial factors and the differences by sexes. The “Questionnaire for students 2002” was applied to 2 532 high school students (ranging from 13 to 22 yearsold). It was found that 14.2 % of the sample has used illegal drugs; the drugs mostly used were tranquilizers, marijuana and cocaine. In our sample, the drug consume (legal and illegal drugs) prevalences howed higher rate than the national reported. Family Influence and personal beliefs were detected as a consume protection factor. Differences by sexes about particular drugs use and the beliefs about them were found. In view of the results deeper studies are necessary.