OBJECTIVE: To design and test the validity of a method to identify homelessness among Medicaid enrollees using mailing address data. DATA SOURCES/STUDY SETTING: Enrollment and claims data on Medicaid expansion enrollees in Hennepin and Ramsey counties who also provided self-reported information on their current housing situation in a psychosocial needs assessment. STUDY DESIGN: Construction of address-based indicators and comparison with self-report data. PRINCIPAL FINDINGS: Among 1,677 enrollees, 427 (25 percent) self-reported homelessness, of whom 328 (77 percent) had at least one positive address indicator. Depending on the type of addresses included in the indicator, sensitivity to detect self-reported homelessness ranged from 30 to 76 percent and specificity from 79 to 97 percent. CONCLUSIONS: An address-based indicator can identify a large proportion of Medicaid enrollees who are experiencing homelessness. This approach may be of interest to researchers, states, and health systems attempting to identify homeless populations.