The aim of this study was to analyze sexual behaviors and attitudes of children 9-14 years old in Spain. In this article we present data from 470 children of which 52% are boys and 48% girls. In order to evaluate the sample, Information, Attitudes and Behaviors related to Health Questionnaire (CIACS-II) was used. Results evidence that boys 9 years old already show behaviors that evidence their interest towards sexuality. 8% have sometimes masturbated and 9% have used pornography for becoming excited. 14% of children 11-12 years old have already had sexual relations and 38% state to have sexual fantasies. Girls start to masturbate and to have sexual relations later than boys and show a prevalence of sexual fantasies and use of pornography very lower. It is necessary sexual education programs to be implanted since early ages in schools.