Papua New Guinea is one of the many former British Commonwealth colonies which maintain the criminalisation of the sexual activities of two groups, despite the fact that the sex takes place between consenting adults in private: sellers of sex and males who have sex with males. The English common law system was imposed on the colonies with little regard for the social regulation and belief systems of the colonised, and in most instances, was retained and developed post-Independence, regardless of the infringements of human rights involved. Now the HIV pandemic has thrown a spotlight, not altogether welcome, on the sexual activities of these two groups. In Papua New Guinea, a growing body of behavioural research has focused on such matters as individual sexual partnering, condom use and awareness of HIV. My work, however, has a different purpose. I chose the terms in the title to highlight a nexus which I believe exists between the criminal law and negative attitudes of society. At an international level, the argument has been put that decriminalising sex work and sodomy will facilitate HIV epidemic management, reducing the stigma and discrimination these groups encounter and making them easier to reach. I undertook my research therefore with the aim of gaining deeper understanding of the effects the current situation of criminalisation might have on the social lives of these criminalised people today, in the country generally and in Port Moresby the capital in particular, and whether these effects might provide evidence to support the argument for law reform.