BACKGROUND: The low uptake of HIV voluntary counseling and testing (VCT), an effective HIV prevention intervention, has hindered global attempts to prevent new HIV infections, as well as limiting the scale-up of HIV care and treatment for the estimated 38 million infected persons. According to UNAIDS, only 10% of HIV-infected individuals worldwide are aware of their HIV status. At this point in the HIV epidemic, a renewed focus has shifted to prevention, and with it, a focus on methods to increase the uptake of HIV VCT. This review discusses home-based HIV VCT delivery models, which, given the low uptake of facility-based testing models, may be an effective avenue to get more patients on treatment and prevent new infections. OBJECTIVES: (1) To identify and critically appraise studies addressing the implementation of home-based HIV voluntary counseling and testing in developing countries. (2) To determine whether home-based HIV voluntary counseling and testing (HBVCT) is associated with improvement in HIV testing outcomes compared to facility-based models. SEARCH STRATEGY: We searched online for published and unpublished studies in MEDLINE (February 2007), EMBASE (February 2007), CENTRAL (February 2007). We also searched databases listing conference proceedings and abstracts; AIDSearch (February 2007), The Cochrane Library (Issue 2, 2007), LILACS, CINAHL and Sociofile. We also contacted authors who have published on the subject of review. SELECTION CRITERIA: We searched for randomized controlled trials (RCTs) and non-randomized trials (e.g., cohort, pre/post-intervention and other observational studies) comparing home-based HIV VCT against other testing models. DATA COLLECTION AND ANALYSIS: We independently selected studies, assessed study quality and extracted data. We expressed findings as odds ratios (OR), and relative Risk (RR) together with their 95% confidence intervals (CI). MAIN RESULTS: We identified one cluster-randomized trial and one pre/post-intervention (cohort) study, which were included in the review. An additional two ongoing RCTs were identified. All identified studies were conducted in developing countries. The two included studies comprised one cluster-randomized trial conducted in an urban area in Lusaka, Zambia and one pre/post-intervention (cohort) study, part of a rural community cohort in Southwestern Uganda. The two studies, while differing in methodology, found very high acceptability and uptake of VCT when testing and or results were offered at home, compared to the standard (facility-based testing and results). In the cluster-randomized trial (n=849), subjects randomized to an optional testing location (including home-based testing) were 4.6 times more likely to accept VCT than those in the facility arm (RR 4.6, 95% CI 3.6-6.2). Similarly, in the pre/post study (n=1868) offering participants the option of home delivery of results increased VCT uptake. In the intervention year (home delivery) participants were 5.23 times more likely to receive their results than during the year when results were available only at the facility. (OR 5.23 95% CI 4.02-6.8). AUTHORS' CONCLUSIONS: Home-based testing and/or delivery of HIV test results at home, rather than in clinics, appears to lead to higher uptake in testing. However, given the limited extant literature and the limitations in the included existing studies, there is not sufficient evidence to recommend large-scale implementation of the home-based testing model.