A study was conducted among patients attending a public health centre in Nairobi, Kenya in order to (a) verify the prevalence of HIV, (b) identify clinical risk factors associated with HIV and (c) determine clinical markers for clinical screening of HIV infection at the health centre level. Of 304 individuals involved in the study,107(35%) were HIV positive. A clinical screening algorithm based on four clinical markers, namely oral thrush, past or present TB, past or present herpes zoster and prurigo would pick out 61 (57%) of the 107 HIV-positive individuals. In a resource-poor setting, introducing a clinical screening algorithm for HIV at the health centre level could provide an opportunity for targeting voluntary counselling and HIV testing, and early access to a range of prevention and care interventions.