It is evident that sexual activity tends to decrease with age. Nonetheless, it is still prevalent enough to be considered a risk factor for the spread of HIV among older people. This paper uses quantitative data for 2053 individuals to examine HIV risk perception and correlates of perceived risk among older people aged 50 years and older living in Nairobi slums. It emerged that a majority of older people did not consider themselves at risk of infection. Of those who felt at risk, a greater proportion sensed only a small chance of contracting HIV. Women cited 'no sexual activity' while men mentioned 'having only one and/or a faithful sexual partner' as the primary reasons for perceiving minimal risk of HIV infection. There were no differences by sex in the basis for perceiving moderate-to-great risk of infection. Religion is a key factor in risk perception with Muslims perceiving higher levels of risk and, conversely, devotees irrespective of faith perceiving lower levels of risk. Older people willing to be tested for HIV had a decreased likelihood of perceived risk compared with those unwilling to be tested. This paper recommends evaluation of older people's perception of risk in order to better inform interventions aimed at minimizing their vulnerability to HIV infection.