Mathematical models and recent data from ecological, observational, and experimental studies show that antiretroviral therapy (ART) is effective for both treatment and prevention of HIV, validating the treatment as prevention (TasP) approach. Data from a variety of settings, including resource-rich and -limited sites, show that patient attrition occurs at each stage of the human immunodeficiency virus (HIV) treatment cascade, starting with the percent unaware of their HIV infection in a population and linkage to care after diagnosis, assessment of ART readiness, receipt of ART, and finally long-term virologic suppression. Therefore, in order to implement TasP, we must first define practical and effective linkage to care, acceptability of treatment, and adherence and retention monitoring strategies, as well as the cost-effectiveness of such strategies. Ending this pandemic will require the combination of political will, resources, and novel effective interventions that are not only feasible and cost effective but also likely to be used in combination across successive steps on the HIV treatment cascade.