Background: The study examined risk factors for having ever contracted sexually transmissible infections (STI) among a high-risk sample in midwestern USA. Methods: A cross sectional survey was conducted among 428 homeless youth aged 16–19 years. Assessed correlates included child maltreatment, street exposure, sexual histories, street experiences and substance use. Results: Multivariate analyses revealed that males were 86% less likely to have had STI compared with females (adjusted odds ratio [AOR] = 0.14; 95% confidence interval [CI] = 0.06–0.31). Blacks were almost four times more likely (AOR = 3.71; 95% CI = 1.80–7.63) and other races were over two times more likely (AOR = 2.25; 95% CI = 1.08–4.67) to have had STI compared with whites. For every one unit increase in the number of times youth ran away, there was a 3% increase in the likelihood of ever having had an STI (AOR = 1.03; 95% CI = 1.01–1.06). For every one unit increase in frequency of condom use there was a 61% decrease in the likelihood of an STI (AOR = 1.39; 95% CI = 1.10–1.76). Finally, youth who traded sex were approximately 2.5 times more likely to have had STI compared with youth who did not trade sex (AOR = 2.36; 95% CI = 1.04–5.34). None of the remaining correlates approached multivariate significance. Conclusions: The amount of time youth spend on the street, their sexual practices, and their subsistence strategies are important correlates of STI and females and non-whites are particularly vulnerable among this high-risk population. (Authors)