Abstract Background Subcutaneous infliximab (IFX-SC) has shown comparable efficacy and safety with IV infliximab in ulcerative colitis (UC) or Crohn's disease (CD) since its launching in 2021. We aimed to investigate the one-year real-life efficacy and durability of IFX-SC in Korea. Methods From September 2021 to November 2023, patients with moderate-to-severe UC or CD, who are naive to any types of biologic agents or IFX were prospectively enrolled from 41 tertiary referral centers in Korea. After IV infliximab induction from Week (W) 0 to W2, patients received IFX-SC every 2 weeks from W6. Patients who administered IFX-SC less than W14 were excluded. Clinical remission (CREM), clinical response (CRES) at W26, W50, and one-year drug survival were assessed. In patients with CD, CREM was defined as Crohn’s disease activity index (CDAI) <150 points, and CRES was defined as a reduction in CDAI ≥70 points from baseline. In patients with UC, CREM was defined as partial Mayo score(pMS) of ≤1 points with no individual subscore of >1 point, and CRES was defined as a reduction from baseline in pMS of ≥2 points and ≥30% along with either a reduction in rectal bleeding subscore (RBS) of ≥1 point or an absolute RBS of ≤1 point19. Drug survival was evaluated based on the time of drug persistence from W0 to the last date of IFX-SC administration among drug-off cases. Results A total of 192 patients (UC with 53, and CD with 139) were enrolled, consisting of about 80% of biologic naïve cohort. Enrolled patients included young adults with a male predominance (Table 1). At W26, patients with UC showed 54.5% CREM and 88.6% CRES (Figure 1A). Among patients with CD, rates of CREM and CRES were 92.1% and 97.0%, respectively. Similarly, W50 CREM and CRES were also favorable with a rate of 57.1% and 89.3% among UC patients. In addition, among CD patients, favorable outcome was more obvious, showing 84.6% and 93.8% of CREM and CRES. Meanwhile, one-year drug survival was also investigated. As shown on the Figure 1B, one-year drug survival probability seemed favorable with a survival rate over 97% in both UC and CD patients (UC; 98.1% at W26 with 95% confidence interval [CI], 0.874–0.852, 96.1% at W50, 95% CI, 0.852–0.990, and CD; 97.8% at W26 with 95% CI, 0.933–0.993, 97.8% at W50 with 95% CI, 0.933–0.993). During the study, 3.1% (six patients) of serious adverse events were reported. Conclusion IFX-SC seems to be efficacious therapeutic option for patients with moderate-to-severe UC or CD patients in real-world settings. With a favorable drug survival and tolerable safety profile, it may facilitate individualized treatment with a good compliance.