Gastric endoscopic resection (ER) is widely performed in Korea. This study aimed to investigate the overall status of gastric ER in Korea. We enrolled ESD or EMR cases performed for gastric cancer and adenoma from 2012 to 2017 by searching the NHIS database. The annual trend of gastric ER and the clinical characteristics were investigated. Institutions were classified into very high-, high-, low-, and very low volume centers (VHVC, HVC, LVC, and VLVC) by the procedure numbers, and institutional types, regional distributions, and medical resources were investigated accordingly. There were 175,370 ER cases during the study period, with an increasing trend over time. The average annual ESD procedure numbers were 3.9, 54.5, 249.5, and 540.3 cases in 131 VLVCs, 119 LVCs, 24 HVCs, and 12 VHVCs, respectively. Among ESD-performing institutions, 44.8% were located in the Seoul Capital Area. The distribution of medical resources showed a positive correlation with the procedural volume. Similar tendencies were also demonstrated in EMR, with some differences in hospital types and regional distribution. Gastric ER and ESD are increasing in Korea. There was a significant variance in the number of ER procedures and the distribution of types, regions, and medical resources according to the procedural volume.