Introduction Sexually Transmitted Infections (STDs) have become an important medical problem in prisons all around the world. Peer education interventions are a frequently utilised strategy for preventing Sexually Transmitted Infections (STIs) worldwide. Our study was aimed to examine the effectiveness of the peer education method in knowledge, attitudes, and practices, regarding to STIs.

Methods A peer education intervention was conducted in a female prison in the northeast of Iran. A cohort of 1098 students was surveyed (n=534 intervention group, n=567 control group) through anonymous questionnaires, both pre- and post-intervention.

Results There were significant differences over time and between intervention and control groups associated with increased STIs knowledge (OR:2.16; 95% CI:1.76, 2.23), reduced equipment sharing among injection drug users (OR:0.43; 95% CI:0.20, 0.52), and increased condom use (OR:2.23; 95% CI:1.69, 2.43). Peer education programs had a significant effect on STI infection (OR: 2.26; 95% CI:1.99, 2.16).

Conclusion Peer education programs in a female prison are effective at improving behavioural, practical and infection outcomes regarding STIs. According to high prevalence of STIs among female inmates, prevention activities targeting this population should be considered.