Objective To assess the prevalence of HIV among men who have sex with men (MSM) in Chongqing, China from 2006 to 2009.

Methods The authors used a snowball sampling method to perform a 3-month cross-sectional study each year from 2006 to 2009. Every participant was asked to complete a questionnaire about demographic and behavioural characteristics, and blood samples were taken for antibody testing for HIV and syphilis.

Results A total of 953, 1015, 743 and 603 participants were investigated in 2006, 2007, 2008 and 2009, respectively. HIV prevalence rates were 10.9%, 12.8%, 10.6% and 19.1%, respectively. The rates increased by 2.3% averagely per year (p<0.001). The HIV prevalence rates were significantly higher than the total population in subjects who were aged more than 40 years, subjects with an educational background of a junior high school level or lower, subjects with a positive syphilis infection or subjects who were recruited from a public bath (p<0.01). The HIV prevalence rates increased on average per year more than 4% in subjects over 30, subjects who worked in the entertainment business, subjects who were married or divorced, subjects with a positive syphilis infection or subjects who were not informed HIV test results. Although most subjects had good HIV/AIDS knowledge awareness (90%), the rate of consistent condom use was low (<37%).

Conclusions The prevalence of HIV is high and is rapidly growing among MSM in Chongqing, China. More appropriate responses are urgently needed to promote a change in the behaviour of MSM.