This guide was developed to support national AIDS program managers and their partners to implement the HIV test–treat–retain cascade analysis at country level. It includes guidance on how to use the cascade model to assess the magnitude and determinants of engagement along the continuum of care and also opportunities to improve the delivery of services to PLHIV and, ultimately, access to HIV testing and treatment.<br><br>It suggests a process for conducting the cascade analysis in country in order to achieve broad stakeholder participation, consensus on the findings of the analysis and ownership of the conclusions and recommendations for improvements resulting from it.