BACKGROUND/AIMS: The differences in the clinical course of Crohn's disease (CD) and ulcerative colitis (UC) among Asian countries remain unknown. Thus, we compared the clinical characteristics, treatment, and one-year outcomes of newly diagnosed inflammatory bowel disease (IBD) patients between Vietnam and Korea. METHODS: A retrospective cohort study was conducted at seven tertiary hospitals in these countries between January 2020 and January 2021. Data on demographics, diseases, treatment, and outcomes during 1 year after diagnosis were collected. RESULTS: Among 225 patients (60 from Vietnam and 165 from Korea), 140 and 85 were diagnosed with UC and CD, respectively. Severe activity (p < 0.01) and extensive colitis (p < 0.01) in UC, along with complicated behavior in CD (p < 0.01), were more frequently observed in Vietnamese patients compared to Korean patients. The proportion of UC patients using corticosteroids (p < 0.01), immunomodulators (p < 0.01), and biologics (p = 0.026) was significantly higher in Vietnam. In contrast, the proportion of UC patients using topical mesalamine (p < 0.01) was significantly higher in Korea. The intervals from CD diagnosis to biologic therapy initiation (p = 0.04), as well as from UC diagnosis to corticosteroid (p < 0.01), immunomodulator (p < 0.01), and biologic therapy (p < 0.01) commencement, were significantly shorter in Vietnamese patients compared to Korean patients. However, the proportions of endoscopic healing and complications at 1-year follow-up did not significantly differ between the countries (p > 0.05). CONCLUSIONS: Although Vietnamese IBD patients had higher baseline clinical and phenotypic severity than their Korean counterparts, no significant differences in short-term outcomes were observed, potentially reflecting the impact of the higher rate and early biologic usage in Vietnamese patients.