Introduction: Due to their physical and psychological vulnerability, adolescent girls are particularly exposed to risks related to unprotected sex and a lack of appropriate health information and services.

Objective: study the knowledge, attitudes and practices of adolescent girls with regard to sexually transmitted infections at the LycéeCollège Notre Dame de l'Assomption.

Patients and method: This was a cross-sectional CAP (knowledge, attitudes and practices) evaluation study conducted over a threemonth period. The Lycée-Collège Notre Dame de l'Assomption served as the setting for the study. The study variables concerned knowledge, attitudes and practices as well as sociodemographic characteristics. Data were collected using a pre-established questionnaire. The data were entered and analysed using SPHINX software.

Results: A total of 205 adolescent girls participated in the study. The average age was 15.93, ranging from 15 to 19 years old. Participants had good knowledge of 35% and average knowledge of 41% of modern contraceptive methods and their use, as well as STIs. As for their attitudes and practices regarding SRH services, 60% and 64% respectively were found to be insufficient.

Conclusion: It appears that adolescents have a fairly thorough knowledge of contraceptive methods and STIs, even if the rate of use remains unsatisfactory. Further study would be necessary to identify the factors contributing to the non-use of contraception by adolescents.