BACKGROUND: There have been deviations in the regional rate of certification in Korean long-term care insurance (LTCI). This study aimed to explore the determinants of the rate of certification in LTCI. METHODS: The panel data of the year 2010–2014 of the 227 National Health Insurance Service (NHIS) regional office were used. Making use of 26 explanatory variables (socio-demographic factors, access to the long-term care services, etc.), we estimated the random effects model using STATA SE ver. 13.0 program (Stata Corp., College Station, TX, USA) and tried to find out the determinants of the regional rate of certification. RESULTS: Estimation results showed that the most important determinants of the regional rate of certification in LTCI are the long-term care infrastructure such as capacity or number of the homecare service institution, sanatorium, or convalescent hospital. The number of the elderly who lives alone and the dimentia patients were positively related to the regional rate of certification in LTCI. CONCLUSION: The estimation results implied that the regional variation in the rate of certification in LTCI has nothing to do with the NHIS regional offices or their employees. To alleviate the deviation in the regional rate of certification in LTCI, we suggested the analysis of the deviation in the survey checklist. We also proposed to found the regional comprehensive support center to prevent the geriatric illness and to improve the residents' health, etc.