Background Home-based HIV testing and counselling (HTC) achieves high uptake, but is difficult and expensive to implement and sustain. We investigated a novel alternative based on HIV self-testing (HIVST). The aim was to evaluate the uptake of testing, accuracy, linkage into care, and health outcomes when highly convenient and flexible but supported access to HIVST kits was provided to a well-defined and closely monitored population. Methods and Findings Following enumeration of 14 neighbourhoods in urban Blantyre, Malawi, trained resident volunteer-counsellors offered oral HIVST kits (OraQuick ADVANCE Rapid HIV-1/2 Antibody Test) to adult (≥16 y old) residents (n = 16,660) and reported community events, with all deaths investigated by verbal autopsy. Written and demonstrated instructions, pre- and post-test counselling, and facilitated HIV care assessment were provided, with a request to return kits and a self-completed questionnaire. Accuracy, residency, and a study-imposed requirement to limit HIVST to one test per year were monitored by home visits in a systematic quality assurance (QA) sample. Overall, 14,004 (crude uptake 83.8%, revised to 76.5% to account for population turnover) residents self-tested during months 1–12, with adolescents (16–19 y) most likely to test. 10,614/14,004 (75.8%) participants shared results with volunteer-counsellors. Of 1,257 (11.8%) HIV-positive participants, 26.0% were already on antiretroviral therapy, and 524 (linkage 56.3%) newly accessed care with a median CD4 count of 250 cells/μl (interquartile range 159–426). HIVST uptake in months 13–24 was more rapid (70.9% uptake by 6 mo), with fewer (7.3%, 95% CI 6.8%–7.8%) positive participants. Being “forced to test”, usually by a main partner, was reported by 2.9% (95% CI 2.6%–3.2%) of 10,017 questionnaire respondents in months 1–12, but satisfaction with HIVST (94.4%) remained high. No HIVST-related partner violence or suicides were reported. HIVST and repeat HTC results agreed in 1,639/1,649 systematically selected (1 in 20) QA participants (99.4%), giving a sensitivity of 93.6% (95% CI 88.2%–97.0%) and a specificity of 99.9% (95% CI 99.6%–100%). Key limitations included use of aggregate data to report uptake of HIVST and being unable to adjust for population turnover. Conclusions Community-based HIVST achieved high coverage in two successive years and was safe, accurate, and acceptable. Proactive HIVST strategies, supported and monitored by communities, could substantially complement existing approaches to providing early HIV diagnosis and periodic repeat testing to adolescents and adults in high-HIV settings., In a prospective study, Augustine Choko and colleagues assess uptake, accuracy, and outcomes of implementation of community-wide HIV self-testing delivered and supported by resident community volunteers in 14 neighborhoods of Blantyre, Malawi., Editors' Summary Background Every year, about 2.1 million people (70% of whom live in sub-Saharan Africa) are newly infected with HIV, the virus that causes AIDS, and 1.5 million people (again, mainly in sub-Saharan Africa) die as a result. HIV, which is usually transmitted through unprotected sex with an infected individual, gradually destroys CD4 lymphocytes and other immune system cells, leaving HIV-positive individuals susceptible to other serious infections and to unusual cancers. HIV is diagnosed by looking for antibodies to HIV in blood or saliva. After diagnosis, the progression of HIV infection is monitored by regularly counting the number of CD4 cells in the blood. Initiation of antiretroviral therapy—a combination of drugs that keeps HIV replication in check but that does not cure the infection—is recommended when an individual’s CD4 count falls below 500 cells/μl or when he or she develops an AIDS-defining condition. Why Was This Study Done? HIV-positive individuals need to know their status so that they can take steps to avoid transmitting the virus to other people (for example, by always using a condom during sexual intercourse) and so that they can begin treatment. Treatment helps to keep HIV-positive individuals healthy but also reduces their chances of transmitting the virus to their sexual partners. Unfortunately, many HIV-positive individuals are unaware of their status. The situation is particularly bad in sub-Saharan Africa, where, despite major investments in facility-based and community-based HIV testing and counseling (HTC) programs, only a quarter of adults have had a recent HIV test, and only half of the people living with HIV know they are HIV positive. Barriers to facility-based HTC include concern about lack of confidentiality and fears of stigmatization. Home-based HTC avoids some of these barriers and can achieve high uptake of testing, but doubts have been expressed about the sustainability of this approach to testing. Here, the researchers evaluate an alternative to home-based HTC—HIV self-testing (HIVST)—by undertaking a community-based prospective study of HIVST in Blantyre, Malawi. HIVST involves individuals performing and interpreting their own HIV test and has the potential to be widely implemented with minimal involvement of trained healthcare workers. What Did the Researchers Do and Find? Trained resident volunteer-counselors offered one oral HIVST kit (a kit that measures HIV in saliva) per year for a two-year period to 16,660 adult residents in 14 neighborhoods in urban Blantyre. All the participants received instructions on how to use the kits, pre- and post-counseling, and, for participants self-testing HIV positive, a referral card to attend an HIV care clinic. The residents also completed a questionnaire about their experience of HIVST. Three-quarters of the residents self-tested in the first and second year of the study. HIVST uptake was more rapid in the second year than in the first year and was high among men and adolescents, two hard-to-reach populations. Three-quarters of the residents who self-tested during the first year of the study shared their results with a volunteer-counselor. Of the 1,257 participants who discovered they were HIV positive during the first year of the study, more than half accessed HIV care. Importantly, 94.4% of the participants reported that they were happy with HIVST even though 2.9% reported being forced to take the test, usually by a main partner; no HIVST-related partner violence or suicides were reported by the study’s community surveillance system. Finally, HIVST and repeat HTC results agreed in 99.4% of participants selected as a quality assurance sample (one in 20 of the participants). What Do These Findings Mean? These findings show that, in urban neighborhoods in Malawi, coverage with community-based HIVST was high (particularly among adolescents and men) in two successive years and that HIVST was safe, accurate, and acceptable. Importantly, HIVST using a delivery model based on trained volunteers led to acceptable linkage into HIV care services, and the approach had a very low incidence of major social harms such as partner violence. Uncertainty about estimates of uptake and linkage to care and other aspects of the study design may limit the accuracy of these results. Nevertheless, these findings suggest that scaling up HIVST could complement existing strategies for providing early HIV diagnosis and periodic repeat testing and could thus have a sustained impact on the coverage of HIV testing and care in Africa and on the control of the HIV/AIDS epidemic. Additional Information This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at http://dx.doi.org/10.1371/journal.pmed.1001873. Information is available from the US National Institute of Allergy and Infectious Diseases on all aspects of HIV infection and AIDS, including testing and diagnosis NAM/aidsmap provides basic information about HIV/AIDS, summaries of recent research findings on HIV care and treatment, and personal stories about living with HIV/AIDS Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including HIV testing, HIV/AIDS treatment and care, and HIV prevention, and on HIV/AIDS in Malawi and in sub-Saharan Africa; Avert also provides personal stories about living with HIV/AIDS The World Health Organization provides information on all aspects of HIV/AIDS (in several languages), including its new consolidated guidelines on HIV testing The UNAIDS Fast-Track Strategy to End the AIDS Epidemic by 2030 provides up-to-date information about the AIDS epidemic and efforts to halt it; UNAIDS also provides detailed region-specific information and policy news.