: OBJECTIVE: The aim of the study was to compare the yields of newly diagnosed cases of HIV infection and advanced immunodeficiency between individuals attending a mobile HIV counselling and testing (HCT) service as participants in a population-based HIV seroprevalence survey and those accessing the same service as volunteers for routine testing. METHODS: The study was conducted in a peri-urban township within the Cape Metropolitan Region, South Africa. Survey participants (recruited testers) were randomly selected, visited at home and invited to attend the mobile HCT service. They received 70 South African Rand food vouchers for participating in the survey, but could choose to test anonymously. The yield of HIV diagnoses was compared with that detected in members of the community who voluntarily attended the same HIV testing facility prior to the survey and did not receive incentives (voluntary testers). RESULTS: A total of 1813 individuals were included in the analysis (936 recruited and 877 voluntary testers). The prevalence of newly diagnosed HIV infection was 10.9% [95% confidence interval (CI) 9.0-13.1%] among recruited testers and 5.0% (3.7-6.7%) among voluntary testers. The prevalence of severe immune deficiency (CD4 count ?200?cells/?L) among recruited and voluntary testers was 17.8% (10.9-26.7%) and 4.6% (0.0-15.4%), respectively. Linkage to HIV care in recruited testers with CD4 counts ?350?cells/?L was 78.8%. CONCLUSION: Compared with routine voluntary HCT, selection and invitation in combination with incentives doubled the yield of newly diagnosed HIV infections and increased the yield almost fourfold of individuals needing antiretroviral therapy. This may be an important strategy to increase community-based HIV diagnosis and access to care.