This Guide was prepared to help CARE Act grantees and planning bodies, particularly Title I and Title II jurisdictions, estimate the number of individuals in your jurisdiction who know they are HIV-positive but are not receiving regular HIV-related primary medical care. The University of California at San Francisco (UCSF) has developed a practical framework you can use to develop a quantitative estimate of unmet need. This Guide explains the reasons you need to estimate unmet need, describes the Unmet Need Framework, and provides practical steps and examples to help you use it in your State or eligible metropolitan area (EMA). The first two sections will help you understand the Unmet Need Framework and why it is important. The other sections will guide you through using it to estimate unmet need in your jurisdiction.