Aim: Although there is a high risk of gastrointestinal (GI) bleeding in the elderly, few studies have quantified the impact of risk factors on GI complications in elderly nonsteroidal anti-inflammatory drug (NSAID) users. This study aimed to develop and validate a risk prediction score to identify high-risk elderly patients using NSAID for severe GI complications. Methods: We used the following two Korean claims datasets: customized data with an enrollment period 2016–2017 for model development, and the sample data in 2019 for external validation. We conducted a nested case-control study for model development and validation. NSAID users were identified as the elderly (≥ 65 years) who received NSAIDs for more than 30 days. Patients who experienced serious GI complications, defined as hospitalizations or emergency department visits, were diagnosed with GI bleeding or perforation. We derived a model using logistic regression and cross-validation. Results: In the external validation cohort, we identified 372 cases from 254,551 patients. We identified 8,176 cases and 81,760 controls with a 1:10 matched follow-up period in the derivation cohort. In the external validation cohort, we identified 372 cases from 254,551 patients. The risk predictors were high-dose NSAIDs, NSAID type, complicated GI ulcer history, male sex, concomitant gastroprotective agents, relevant co-medications, severe renal disease, and cirrhosis. Area under the receiver operating characteristic curves was 0.77 (95% confidence interval, 0.75–0.80) in the external validation dataset. Conclusion: The prediction model may be a useful tool for reducing the risk of serious GI complications by identifying high-risk elderly patients.