To inform future intervention programmes, the purpose of this paper is to explore the psychosocial and contextual determinants of intention to reduce risky sexual behaviour amongst inmates in South African prisons.A cross sectional study using interviewer administered questionnaires was conducted with 357 inmates across four prison facilities in South Africa that were involved in a pre-release health education intervention for parolees in two provinces.About 65 per cent of participants were first time offenders. Almost 50 per cent were unemployed prior to arrest and 66 per cent were married at time of incarceration. Self-efficacy, general life skills efficacy and sexual communication were the strongest predictors of intention to reduce risky behaviour upon release. High intenders were significantly different from low intenders in their self-efficacy, sexual communication, attitudes towards condom use and the perceived norm of sex being a non-utilitarian transaction.One of the key limitations is the low literacy levels amongst prison inmates. Data also relied heavily on self reports of behaviours that may have occurred prior to the participants being incarcerated.It is concluded that the exploration of subpopulation specific behavioural determinants is a critical step in the development of effective, contextually-relevant, health education interventions.