ABSTRACT: The sexual health of clients has been poorly addressed by mental health service providers and sexually transmissible infection (STI) incidence rates are increasing among young people. A self-report questionnaire was used to gather information in order to describe and to conduct a cross-sectional analysis of sexual health knowledge, risk behaviour and STI screening history among young people who have experienced a first episode of psychosis, who present to community-based early psychosis programmes in south-eastern Sydney. STI knowledge was fair and sexual risk practice knowledge was poor regarding anal and oral sex. Women reported significantly more sexual partners than men. When those young people who had had unsafe sex attended for STI screens only, 5% received a complete screen. The survey result indicates a need for sexual health screening education to be conducted for clients. Against a background of escalating rates of HIV, STIs and high risk-taking behaviours among young people, it is essential that mental health staff are provided with the skills and education to address sexual health and harm minimization issues.