Abstract Background Sexual violence is considered a serious violation of human rights which affects mainly young women and adolescents. There is little information about the conditions under which sexual offences occur. We evaluated characteristics of sexual violence against adolescent girls and adult women. Method This is a quantitative, retrospective, descriptive study of sexual violence against adolescent girls and adult women. Analyses were carried out on data collected from 1118 women, 546 adolescents (10-19 years) and 572 adults (≥ 20 years), with a complaint of rape treated at Hospital Pérola Byington, São Paulo, between 1994 and 1999. The age limit of the adolescent sample met the World Health Organization’s (WHO) criteria. We analyzed the type of sexual contact, degree of intimidation, perpetrator and activity of the victim during the approach. Results Crimes without penetration were five times more frequent in adolescents and use of threats of death or intimidation was common in both groups. Mental illness was more prevalent in adult victims and the majority of adolescent victims were aged