The long-term efficacy and safety of infliximab (IFX) in Japanese children with inflammatory bowel disease (IBD) remain unclear. This study aimed to examine the long-term outcomes of IFX treatment in Japanese children with IBD. We retrospectively recruited patients aged <16 years who were diagnosed with ulcerative colitis (UC) or Crohn's disease (CD) at Kurume University Hospital in Japan between 2011 and 2022 and examined the effectiveness and safety of IFX. We characterized the responses to IFX as primary response, primary nonresponse (PNR), secondary loss of response (sLOR), or still receiving IFX. Among the 77 enrolled patients with UC (median age, 10 years) and 48 with CD (median age, 12 years), 55 (27 with UC and 28 with CD) received IFX treatment. IFX treatment was significantly more common in patients with CD (58.3%) than in those with UC (35.1%; p=0.016). The PNR was significantly greater in patients with UC (18.5%) than in those with CD (0.0%; p=0.023), as was the sLOR (UC, 51.9%; CD, 21.4%; p=0.026). The likelihood of continuing IFX treatment during follow-up (median, 38 months) was significantly higher in patients with CD (71.4%) than in those with UC (29.6%; p=0.003). Adverse events resulting in the discontinuation of IFX occurred in 3.6% of the patients; one patient with CD developed leukemia, and the other had a serious infusion reaction. The long-term durability of IFX in Japanese pediatric patients with IBD was inadequate in UC compared with CD. Serious adverse events in 3.6% of patients required discontinuation.