BackgroundThe increasing numbers of people living with HIV (PLHIV) who are receiving antiretroviral therapy (ART) have near normal life-expectancy, resulting in more people living with HIV over the age of 50 years (PLHIV50+). Estimates of the number of PLHIV50+ are needed for the development of tailored therapeutic and prevention interventions at country, regional and global level.MethodsThe AIDS Impact Module of the Spectrum software was used to compute the numbers of PLHIV, new infections, and AIDS-related deaths for PLHIV50+ for the years 2000–2016. Projections until 2020 were calculated based on an assumed ART scale-up to 81% coverage by 2020, consistent with the UNAIDS 90–90–90 treatment targets.ResultsGlobally, there were 5.7 million [4.7 million– 6.6 million] PLHIV50+ in 2016. The proportion of PLHIV50+ increased substantially from 8% in 2000 to 16% in 2016 and is expected to increase to 21% by 2020. In 2016, 80% of PLHIV50+ lived in low- and middle-income countries (LMICs), with Eastern and Southern Africa containing the largest number of PLHIV50+. While the proportion of PLHIV50+ was greater in high income countries, LMICs have higher numbers of PLHIV50+ that are expected to continue to increase by 2020.ConclusionsThe number of PLHIV50+ has increased dramatically since 2000 and this is expected to continue by 2020, especially in LMICs. HIV prevention campaigns, testing and treatment programs should also focus on the specific needs of PLHIV50+. Integrated health and social services should be developed to cater for the changing physical, psychological and social needs of PLHIV50+, many of whom will need to use HIV and non-HIV services.