Objective To determine the prevalence of HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM) in Zagreb, Croatia, and assess correlates of testing for HIV in the past 12 months.

Methods The authors carried out a bio-behavioural survey using respondent-driven sampling (RDS) from September 2010 to February 2011. Participants completed a questionnaire and were asked to provide blood, urine, oropharyngeal and rectal swabs for the detection of infections. Data were analysed using RDS Analysis Tool 6.0.1 and STATA V.8.0.

Results A total of 387 MSM were recruited at the University Hospital for Infectious Diseases. The age range of recruited men was 18–57 years. HIV prevalence was 2.8% (95% CI 1.1% to 5.1%) (3.6%, unadjusted), lower than that found in the first RDS survey carried out in 2006 (4.5%, 95% 2.2% to 7.3%) (4.9%, unadjusted). The seroprevalence of herpes virus type 2 was 5.9% (6.9, unadjusted) and that of syphilis measured by Treponema pallidum haemagglutination assay was 7.6% (6.7%, unadjusted). The authors found urethral and/or rectal infections with Chlamydia trachomatis in 7.2% (8.5%, unadjusted) of men and gonoccocal in 2.7% (2.1%, unadjusted). HIV testing in the past 12 months was reported by 32.7% (38.9%, unadjusted). In the multivariate analysis, significant correlates of recent HIV testing were having more than three partners in the past 12 months and the knowledge of HIV status of a regular partner.

Conclusions The results indicate that there might have not been a progression of an HIV and STI epidemic in the past 5 years among MSM in Croatia. Prevention should expand by providing better uptake of HIV and STI testing services, thus enabling timely treatment.