OBJECTIVES: Public insurance for the poor (Medicaid) in the United States often results in poor continuity of coverage due to the phenomenon of “churning.” Churning occurs when individuals lose and regain coverage in a short period of time. Gaps occur within the Medicaid program because of changes in family circumstances that make individuals ineligible for public insurance or because of administrative complexity that result in failure to renew coverage. The purpose of this study is to evaluate the impact of insurance transitions on health care utilization among the publicly insured non-elderly. METHODS: We used the Medical Expenditure Panel Survey (MEPS) for years 2000-2004 for this study. MEPS provides monthly insurance status and resource utilization. Additionally, MEPS contains detailed demographic, socioeconomic and health status information. We estimated the number of transitions for an individual using monthly insurance data. We estimated resource utilization using the total number of inpatient hospitalizations, emergency room visits, outpatient visits, and total number of prescriptions. Number of inpatient hospitalization and emergency room visits were modeled using zero-inflated negative binomial models, while outpatient visits and prescription drugs were modeled using negative binomial models. RESULTS: Our sample has 35,779 individuals, of whom 10,754 had one transition into or out of Medicaid and 2,448 had more than one transition. We find that individuals with multiple transitions tend to have 46% more hospitalizations and use the emergency room 13% more. However, these individuals have 37% lower prescription drug utilization and 12% less outpatient physician visits relative to those who are continuously insured by Medicaid. CONCLUSION: Utilization of emergency and inpatient services were significantly higher, while use of outpatient care and prescription drugs was significantly lower for beneficiaries with interruption in Medicaid coverage. These findings point to the need for further research to assess the impact of churning in this population.