We investigated the potential genetic variants using whole exome sequencing (WES) and evalu-ated the disease course using T cell receptor (TCR) repertoire analysis in rheumatoid arthritis (RA). Fourteen patients with RA and five healthy controls (HCs) were enrolled. For patients with RA, only naïve patients were recruited before treatment, and data were collected at baseline and 6 and 12 months after the initiation of disease-modifying antirheumatic drug (DMARD) treatment. Laboratory data and disease parameters were also collected. Genetic variants were detected using WES, and the diversity of the TCR repertoire was assessed using Shannon-Weiner diversity. Some variants were detected by WES, but their clinical significance should be confirmed by further studies. The diversity of the TCR repertoire in patients with RA was lower than that in HCs; however, after DMARD treatment, it increased significantly. The diversity was negatively cor-related with laboratory findings and disease measures with statistical significance. Variants with a potential for RA pathogenesis were identified and the clinical significance of TCR repertoire was evaluated in Korean patients with RA. Further studies are required to confirm the findings of the present study.