The 2013 World Health Organization's (WHO) Consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection provide more than 50 new recommendations across the continuum of HIV care, including recommendations on HIV testing, using antiretroviral drugs for prevention, linking individuals to HIV care and treatment services, initiating and maintaining antiretroviral therapy (ART) and monitoring treatment. Guidance is provided across all age groups and populations of adults, pregnant and breastfeeding women, adolescents and key populations. The guidelines are based on a public health approach to expanding the use of ARV drugs for HIV treatment and prevention, with a particular focus on resource-limited settings. The most important new clinical recommendations include: treating adults, adolescents and older children earlier - starting ART in all individuals with a CD4 cell count of 500 cells/mm(3) or less (but giving priority to those with advanced clinical disease or a CD4 cell count less than 350 cells/mm(3)); starting ART at any CD4 cell count in certain populations, including those with active TB (existing recommendation), Hepatitis B infection and severe chronic liver disease, HIV-positive partners in serodiscordant couples (existing recommendation), pregnant and breastfeeding women, and children younger than 5 years of age; a preferred first-line ART regimen of Tenofovir+3TC or FTC+ Efavirenz as a once-daily fixed-dose combination for adults, pregnant women, and children aged 3 years and older; and the use of viral load testing as the preferred approach to monitoring the response to ART and to diagnose treatment failure. Guidance is also provided on enhancing the efficiency and effectiveness of HIV services, including strategies to improve retention in care, and adherence to ART; task-shifting to address human resource gaps; decentralizing delivery of ART to primary health care, and integrating ART services within maternal and child health, TB or drug dependency clinics. There is additional guidance for programme managers on how to plan HIV programmes and use resources most efficiently.