OBJECTIVES: The study examined medical care utilisation by health insurance status changes. SETTING: The Korean Welfare Panel Study (KoWePs) was used. PARTICIPANTS: This study analysed 14,267 participants at baseline (2006). INTERVENTIONS: The individuals were categorised into four health insurance status groups: continuous health insurance, change from health insurance to Medical Aid, change from Medical Aid to health insurance, or continuous Medical Aid. PRIMARY AND SECONDARY OUTCOME MEASURES: Three dependent variables were also analysed: days spent in hospital: number of outpatient visits: and hospitalisations per year. Longitudinal data analysis was used to determine whether changes in health insurance status were associated with healthcare utilisation. RESULTS: The number of outpatient visits per year was 0.1.363 times higher (p<0.0001) in the continuous Medical Aid than in the continuous health insurance group. The number of hospitalisations per year was 1.560 times higher (p<0.001) in new Medical Aid and -0.636 times lower (p<0.001) in new health insurance than in continuous health insurance group. The number of days spent in hospital per year was -0.567 times lower (p=0.021) in the new health insurance than in the continuous health insurance group. CONCLUSIONS: Health insurance beneficiaries with a coverage level lower than Medical Aid showed lower healthcare utilisation, as measured by the number of hospitalisations and days spent in hospital per year.