Objectives To investigate the epidemiology and risk factors of gonorrhoea (GC) or chlamydia (CT) coinfection in an HIV-positive US military cohort, focusing on the time after participants' knowledge of HIV diagnosis.

Methods The authors analysed data from 4461 participants enrolled in the US Military Natural History Study cohort for GC or CT infection ≥6 months after their HIV-positive test.

Results During a mean follow-up of 7.08 years, 482 (11%) participants acquired a GC or CT infection. Of these, 283 (6%) acquired a GC infection, 278 (6%) acquired a CT infection and 123 (3%) had multiple GC or CT infections during follow-up. Risk of GC or CT infection was significantly greater in those younger, male, African–American and with a history of GC or CT infection.

Conclusions Frequent GC and CT diagnoses observed among members of this HIV-positive cohort indicate substantial ongoing risk behaviours that raise concerns for HIV transmission and underscore the need for continued screening to help identify and treat these sexually transmitted infections in this population.