This paper reports on an exploratory study examining the role of sexual cleansing rituals in the transmission of HIV among the Luo community in western Kenya. Data were collected using both in-depth interviews and focus group discussions. The study population consisted of 38 widows, 12 community elders and 44 cleansers. Data were collected on non-behavioural causes, behavioural causes and behavioural indicators associated with sexual rituals. Content analysis revealed five central themes: the effect of the ritual on sexual behaviours; factors contributing to the continued practice of the ritual, including a sub-theme on the commercialization of the ritual; the inseparable relationship between the sanctity of sex, prosperity and fertility of the land; and the effects of modernization on the ritual, including a sub-theme on the effects of mass media on HIV-prevention awareness campaigns. Causal factors of unchanging sexual behaviours are deeply rooted in traditional beliefs, which the community uphold strongly. These beliefs encourage men and women to have multiple sexual partners in a context where the use of condoms is rejected and little HIV testing is carried out.