Objective: The present research aims to identify the relation between at risk on-line behaviour (as sexting), self-esteem and the influence of media on bodyimage. According to the literature, our hypothesis suggests that on line behavior is influenced by self-esteem and body-image perception. Design and Method: 500 female participants (range 14-25) filled out self-report questionnaires about socio-anagraphical information, health and sexual behaviour (a.e. BMI, contraception, sexual experiences). Italian versions of Sexting Behaviour Scale, Sociocultural Attitudes Towards Appearance Questionnaire-3 and Multidimensional Self Concept Scale, Cyberbulliyng Questionnaire were administered too. Results: Our results suggest that there are several differences between female adolescents and young adult women, especially for what concern sexual health and body image perception. Higher scores in the Sexting Behaviour Scale were associated with higher scores in the SATAQ subscales concerning internalization, suggesting that they perceive their body as not in shape as they want it to be. Moreover, we found that having a strong self-esteem was a protective factor from the pressure of TV and Magazines. Conclusions: Our results highlighted the relation between on line and offline sexual health, self-esteem and the influence of media on self-perception. Adolescents should be considered at high risk for development of psychological and health problem related to on line behaviour. Therefore it is extremely important for prevention to focus on intervention in schools to enhance self-efficacy in girls and young women, and to develop specific programs to show the risk of the use of internet.