Introduction The study aimed to assess the prevalence of Neisseria gonorrhoeae and Chlamydia trachomatis infections and identify demographic, behavioural and clinical factors correlated with such infections in men attending six sexually transmitted disease clinics in Brazil.

Methods Multicentric, cross-sectional study performed among men attending STD clinics in Brazil. The study included STD clinics in six cities distributed throughout the five geographic regions of Brazil in 2005. Patients provided 20 ml of first catch urine for testing for N gonorrhoeae and C trachomatis by DNA-PCR.

Results A total of 767 (92.9%) men were included in the study. The mean age was 26.5 (SD 8.3) years old. Prevalence of Chlamydia infection was 13.1% (95% CI 10.7% to 15.5%) and gonorrhoea was 18.4% (95% CI 15.7% to 21.1%). Coinfection prevalence was 4.4% (95% CI 2.95% to 5.85%) in men who sought attendance in STI clinics. Factors identified as associated with C trachomatis were younger age (15–24) (OR=1.4 (95% CI 1.01 to 1.91)), present urethral discharge (OR=4.8 (95% CI 1.52 to 15.05)), genital warts (OR=3.0 (95% CI 1.49 to 5.92)) and previous history of urethral discharge (OR=2.4 (95% CI 1.11-5.18)]. Variables associated with gonorrhoea were younger age (15 to 24) [OR=1.5 (95% CI 1.09-2.05)], presence of urethral discharge [OR=9.9 (95% CI 5.53-17.79)], genital warts [OR=18.3 (95% CI 8.03-41.60)] and ulcer present upon clinical examination [OR=4.9 (95% CI 1.06-22.73)]. Conclusions—These findings have important implications for education and prevention actions directed towards men at risk of HIV/STD. A venue-based approach to offer routine screening for young men in STD clinics should be stimulated.