Analysis of the data revealed that adolescent tobacco use is increasingly frequent among females. Alcohol use continues to be widespread among Spanish pre-adolescents and adolescents. Alcohol use begins in childhood and becomes consolidated in adolescence. The results suggest, in relation to gender differences in the use of tobacco, alcohol, and non-institutionalized drugs, that there is a strong tendency toward the homogenization of these habits between genders. It is necessary to emphasize the preventive measures of drug dependence among Spanish pre-adolescents and adolescents.