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Methotrexate is an immunomodulator used paediatric IBD. It is typically second line to thiopurines. This study aimed to describe reasons for methotrexate use and outcomes of methotrexate treatment at a tertiary referral centre.A retrospective analysis of medical records from IBD diagnosis until October 2024 was performed for all paediatric IBD patients currently using methotrexate. Demographics, diagnosis, use of thiopurine and biologic medication, rationale for methotrexate use, tolerance, and response to methotrexate treatment based on serum inflammatory markers, faecal calprotectin and endoscopic re-assessment were analysed.27 patients were identified (see table 1).Abstract OC35 Table 1Patients taking methotrexateM:F 14:13 Mean age at diagnosis (years) 10 Mean age when starting methotrexate (years) 12 IBD diagnosis Crohn’s 24 89% Ulcerative colitis 1 4% IBDU 2 7% VEOIBD ≤ 6 years at diagnosis 7 26% 22/27 (81%) used a thiopurine prior to starting methotrexate. The reasons for switch to methotrexate were failure of disease control (6/22, 27%) or adverse effect of thiopurines (17/22, 77%), including pancreatitis (9/22 41%), myeloid suppression (4/22, 18%), out-of-range thiopurine metabolites (3/22, 14%) and hepatotoxicity (2/22, 9%).5/27 (19%) started methotrexate as their first immunomodulator. The reasons for this decision were low TPMT levels (2/5, 40%), rheumatological co-pathology (2/5, 40%), and parental preference (1/5, 20%).21/27 (78%) also use biologic therapy, with 15/27 (56%) having tried more than one biologic.26/27 patients received methotrexate subcutaneously. This was tolerated in 19/26 (73%), and the remaining 7/26 cases have been switched to oral; 6/7 (86%) for nausea/vomiting, 2/7 (29%) for abnormal LFTs, 1/7 (14%) for redness at injection site, and 1/7 (14%) for psychological disturbance. These seven patients continue to tolerate oral methotrexate.Serum inflammatory markers (CRP, ESR, orosomucoid) were compared prior to methotrexate, at three months and six months. There was an improvement in at least two out of the three inflammatory markers at three months (17/23, 74%) and six months (13/22, 59%). Faecal calprotectin was compared prior to methotrexate and at 3–12 months. Improvement was seen in 9/12 (75%); however, it was not possible to identify calprotectin results in an appropriate time frame in 15/27 cases (56%). Of note, two patients were switched to methotrexate due to severe active Crohn’s disease on their fourth biologic, prior to consideration of a JAK inhibitor or alternative biologic, and have had improvement in clinical symptoms and inflammatory markers (not yet endoscopically reevaluated).6/27 patients (22%) had endoscopic reassessment within 12 months of starting methotrexate. Of these, 5/6 had significant active disease.Limitations are the retrospective nature and small sample size of the study. 5/6 who were endoscopically reassessed had ongoing active disease. They may have been selected for reassessment due to ongoing symptoms, potentially biasing findings.In summary, methotrexate is generally well tolerated and is a viable alternative to thiopurines. Switch from subcutaneous to oral methotrexate can alleviate associated nausea and vomiting. Switch of immunomodulator may be beneficial in patients who have failed multiple biologics with azathioprine. Endoscopic re-evaluation is important for full assessment of response to treatment.