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.