Background: In Tanzania, a country with 1.4 million persons living with HIV (PLHIV), information is needed on services that can help diagnose 90% of PLHIV, initiate and retain on antiretroviral therapy (ART) 90% of those diagnosed, and achieve viral load suppression (VLS) among 90% of those on ART (90-90-90). The Bukoba Combination Prevention Evaluation (BCPE) aimed to achieve 90-90-90 in Bukoba Municipal Council (Bukoba) by scaling up new HIV testing, linkage to care, and ART retention interventions. Method: Located on the western shore of Lake Victoria, Bukoba is a mixed urban and rural council of approximately 150,000 residents. BCPE interventions were implemented throughout Bukoba during October 2014 — March 2017 when national ART-eligibility guidelines expanded from CD4 <350/μL (October 2014) to <500/μL (December 2015) to any CD4 count [(Test and Start (T&S), October 2016]. Pre- and post-intervention, population-based household surveys in 2014 and 2017 assessed among Bukoba residents aged 18-49 years population prevalence of undiagnosed HIV infection and ART coverage among all PLHIV, and progress towards 90-90-90. Findings: After a 2.5 year combination-prevention intervention in Bukoba, prevalence of undiagnosed HIV infection decreased by over half overall (4.7% to 2.0%) and among men (4.3% to 1.9%), and two-thirds among persons aged 18-29 years (3.9% to 1.3%). Among all PLHIV aged 18-49 years, current ART use increased two-fold overall (32.2% to 70.9%), nearly three-fold (23.0% to 62.0%) among men, and four-fold (16.7% to 64.4%) among persons aged 18-29 years. Among PLHIV aged 18-49 years, diagnostic coverage increased from 47.4% to 76.2%, ART use among diagnosed PLHIV increased from 68.0% to 93.1%, and VLS of those on ART increased from 88.7% to 91.3%. Interpretation: Benefiting from only 6 months of T&S, BCPE findings suggest scaling up recommended HIV testing, linkage, and retention interventions can substantially reduce prevalence of undiagnosed HIV infection, increase ART use among all PLHIV, and make substantial progress towards achieving 90-90-90 in a relatively short period. BCPE facility-based test and linkage interventions are undergoing national scale up to help achieve 90-90-90 in Tanzania. Funding Statement: This research was supported by the United States’ President’s Emergency Plan for AIDS Relief through the U.S. Centers for Disease Control and Prevention under the terms of cooperative agreement 5UGPS001998-05. Declaration of Interests: The authors report no conflicts of interest. Ethics Approval Statement: Institutional review boards of the Government of Tanzania, National Institute for Medical Research (NIMR) and Columbia University approved BCPE HTS, LCM, and DT interventions, and all survey methods and data-collection activities. The study was also reviewed and approved in accordance with CDC human research protection procedures. Written informed consent was obtained for pre- and post-intervention survey participants.