Thirty-eight from a total of 42 known HIV-positive prisoners in the Irish prison system voluntarily cooperated in a survey of psychological attitudes, knowledge of risk behaviour, intentions with respect to future risk behaviour, and actual past risk behaviour. Of this group, 65% reported that they had put others at risk of HIV, since they became aware of their own HIV+ status. Only 16% stated that they would definitely not share their drug-taking equipment in the future and 32% that they would always use a condom in sexual intercourse. In general, psychological and biographical variables were not strongly related to whether or not the respondents had put others at risk of HIV. Nor were there any significant differences in knowledge of at risk behaviour between those who had and those who had not put others at risk. However, there was some evidence for considerable independence between risk-taking behaviour in the sexual and in the drug-taking domains, in that risk-taking in one area was not highly predictive of risk-taking in the other.