Between 1950 and 1985, tens of thousands of South Africans were arrested for contravening the Immorality Act (1950) that prohibited extramarital heterosex between whites and blacks and was extended in 1957 to also criminalize the attempt to have interracial sex. Aimed at maintaining whites’ mythical purity, the law was both a weapon to mould the sexual behaviour of transgressive heterosexual white men and a means to constitute race and reproduce racial inequality. Implementing the law inflicted great harms, not only on white men, but also on the Black women with whom they were arrested, harms that were gendered, racialized and sexualized in particular ways. In this presentation, Prof Susanne M. Klausen discusses the state’s policing of ‘mixed’ sex during apartheid, from its role in cultivating a culture of surveillance, to the brutal methods of enforcement, to some of the ways the ugly “lessons learned” about race, desire and sex continue to haunt South Africa today. Firstly, she discussed why a law criminalizing sexual desire was enacted. Then, how the law was implemented with an emphasis on the creation of severe social surveillance, and thirdly, some of what she thinks are the ongoing effects or afterlives of the Immorality Act.