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Patients with very-early onset inflammatory bowel disease (VEOIBD) have been reported to have decreased response rate to infliximab. Younger children have unique drug pharmacokinetics, which risks insufficient drug exposure. We aim to assess infliximab dosing regimens and outcomes in children with VEOIBD compared to older children in a centre routinely using protocol-based proactive therapeutic drug monitoring (TDM).We analysed a prospectively identified cohort of patients with VEOIBD diagnosed between January 1, 2018, and June 30, 2025, at a single tertiary centre. Patients requiring infliximab were matched by sex, IBD phenotype, and infliximab initiation date with controls aged 6–10 and ≥11 years. Data were retrospectively obtained from electronic medical records, including phenotypic details; disease activity scores, inflammatory markers at baseline, week 12, and week 52; infliximab dose, frequency, and trough levels for doses 1–7; current regimens, antibodies and adverse events.Fifteen patients with VEOIBD commenced infliximab (8/15 [53%] male, median [IQR] age at diagnosis 4.2 [1.5-5.0] years, 6/15 (40%) monogenic disease) and were compared to 30 matched controls (6-10 year group, 7/15 [46.7%] male, median age at diagnosis 8.4 [7.4-9.5] years; 11+ group (8/15 [53%] male, median [IQR] age at diagnosis 12.2 [10.9-13.7] years). The median [IQR] length of follow-up was comparable between groups (VEOIBD: 2.9 [1.6-4.4] years, 6-10 group 3.3 [2.9-4.1] years, 11+ group 3.2 [1.7-5.5] years, p=0.74). Dose 3 trough levels were lower in the VEOIBD group (VEOIBD median 14.2 versus control 19.7, p=0.045). There was a trend towards a shorter interval between dose 3 and 4 (VEOIBD 6.4 weeks vs controls 8.0 weeks, p=0.055) and the requirement for dose/interval escalation immediately post-induction (VEOIBD 8/15 vs 8/30, p=0.07). Through the study, patients with VEOIBD had higher median [IQR] doses (VEOIBD 10 [10.0-12.5] mg/kg vs Controls 10 [10.0-10.0] mg/kg, p=0.01) and shorter median [IQR] dosing interval (VEOIBD 4.0 [3.6-4.0] weekly vs Controls 6.0 [4.0-6.0] weekly. The proportion of patients with moderate to severe disease compared to those in remission or mild disease was similar between the groups at baseline, 12 weeks, and 52 weeks (p = 0.60, p = 0.52, p = 0.22, respectively). Faecal calprotectin (μg/g stool) at each time point was similar between groups (Baseline VEOIBD 1800 vs Controls 1701, p=0.83; Week 12 VEOIBD 492 vs 332, p=0.68; Week 52 VEOIBD 420 vs 228).In our cohort, patients with VEOIBD had comparable outcomes to matched controls with later onset IBD, however, required more intensive dosing up to year 3. Pharmacokinetic studies may support the hypothesis of more rapid drug clearance in VEOIBD and the use of dosing based on body surface area should be further explored.