Data were collected from 88 homeless persons in Port-of-Spain, Trinidad to assess HIV risk. 68% of the sample were engaging in unprotected sex with multiple partners, 25% were exchanging sex for money, and 29.5% were regularly smoking crack cocaine. Many had two or more of these behaviours that put them at high risk of HIV infection. Females were significantly more likely to be sex traders, to engage in bisexual behaviour and to have a history of psychiatric illness. The relationship between psychiatric illness and HIV risk behaviours among homeless female persons is explored. Educational interventions are suggested to reduce the public health risks in this population.