Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to relieve pain and reduce inflammation; however, their safety profiles vary among individuals. We conducted a genome-wide association study (GWAS) to identify genetic variants associated with NSAID-related adverse events. A total of 402 patients were recruited from Chungbuk National University Hospital and Ajou University Hospital. Genomic DNA was extracted from blood samples and genotyped using the Korean chip (K-chip), analyzing 7,684,889 single-nucleotide polymorphisms (SNPs). A multivariable logistic regression model adjusted for age and sex was applied, using a suggestive significance threshold of p < 1×10⁻5 due to the small sample size. Among 402 patients, 90 experienced NSAID-related gastrointestinal adverse events. GWAS identified several SNPs associated with gastrointestinal adverse events, with top candidates including rs74475327, rs2725581, rs7914513, rs78430186, rs185260285, rs8130411, and rs74397925. The strongest association was observed on chromosome 3 at rs74475327 (p = 1.44×10⁻6) within ZNF385D. This study provides insight into genetic factors influencing NSAID-related adverse events in Koreans and offers a foundation for further validation and mechanistic studies. Follow-up analyses in independent cohorts will help strengthen these findings.