It is well known that homeless individuals are at risk for a variety of health problems, including sexually transmissible infections. Optimisation of health services for the homeless requires knowledge of their sexual health. The sexual health and sexual vulnerability factors of 500 homeless adults (196 women) were assessed in a cross-sectional survey in three Canadian cities. Our data indicate that a significant proportion of individuals and more women than men reported multiple experiences that compromise their sexual health exponentially. These findings may inform health policies related to sexuality to foster positive sexual health outcomes for all people, including marginalised populations.