2 for comparisons of proportions. In the period of the study, 105 transgender individuals were identified in a population of 4118 patients tested. The prevalence of HIV infection in the transgender group was 27.6% (29/105), while in the non transgender group was 6.2% (247/4013) p:0.0000. Low level of formal instruction, alcohol consumption, drug abuse, previous history of STI and sex work (100% transgenders and 2.3% of non-transgenders) were significantly more frequent in the transgender. The referred correct use of condom was similar in both groups. The prevalence of syphilis was 42.3% in transgender group and 18.1% in non-transgender individuals. These data show that this population has a very high prevalence of HIV-1 and STI. This information could be instrumental to design targets for intensive HIV prevention strategies in this particular high risk population.