Background/Aims: Risks of long-term steroid use in patients with ulcerative colitis (UC) outweigh the benefits, thus dosing should be tapered once a response is achieved. Colonoscopy is a key technique for assessing disease severity and optimizing treatment involving steroids. This retrospective longitudinal cohort study of patients with UC explored factors associated with the duration of systemic steroid use. Methods: The Japan Medical Data Center database, an employer-based insurance claims database, was used to select individuals initiating prednisolone, with a prescription issued between January 1, 2010, and January 31, 2018. The study included adults with a confirmed diagnosis of UC, who had received ≥1 year of continuous treatment with 5-aminosalicylic acid, biologics, or thiopurine. Factors associated with prednisolone duration were assessed using a multivariate regression model. Results: Median duration of prednisolone treatment was 98 days, and colonoscopy was performed ≤1 month before or at the first prescription of prednisolone (index date) in 32.8% of patients (607/1,853). Shorter durations of prednisolone treatment were associated with colonoscopy ≤1 month before or at the index date and higher prednisolone dose at index date, with incidence rate ratios (IRRs) of 0.776 (95% confidence interval [CI], 0.682–0.884; P<0.001) and 0.998 (95% CI, 0.996–1.000; P=0.018), respectively. Charlson Comorbidity Index scores of 1 and ≥2 predicted longer prednisolone treatment (IRR, 1.332; 95% CI, 1.174–1.511; P<0.001 and IRR, 1.599; 95% CI, 1.357–1.885; P<0.001, respectively). Conclusions Performing colonoscopy before or at the time of initiating steroid was associated with a shorter duration of steroid use in patients with UC.