Background/Aims: Sarcopenia is implicated in inflammatory bowel disease (IBD) complications and surgical outcomes. This study aimed to investigate the prevalence and follow-up of sarcopenia in patients with IBD. Methods: Consecutive consenting patients with IBD aged > 18 years were included. Patients with associated sarcopenic diseases were excluded. All had measurements of anthropometry, body mass index (BMI), mid-arm muscle circumference, muscle strength, physical performance, and muscle mass (on computed tomography scan). They were followed up for up to 12 months, and incidence of flares, fractures, and surgery was noted. Results: Of 157 patients screened, 35 refused participation; 5 with associated sarcopenic diseases were excluded. Of 117 patients (median age, 41 years; interquartile range, 18–81 years; 65 men), 73 had ulcerative colitis, 42 Crohn’s disease, and 2 IBD-unclassified. Forty (34.2%) had probable sarcopenia; 47 (40.2%) had sarcopenia (29 ulcerative colitis and 18 Crohn’s disease) including 10 (8.5%) with severe sarcopenia. Ten (21.3%) were in disease remission. Of factors associated with sarcopenia in univariate analysis, only BMI was significant in multivariate analysis. Ninety-nine patients followed up for a median of 7 months (interquartile range, 2–12 months). Freedom from flares was 5.3% in patients with sarcopenia and 46.1% in those without (P= 0.004). Three patients (1 with sarcopenia, 2 without) required surgery. Conclusions Sarcopenia was present in 40% of patients with IBD; one-fifth of these had severe sarcopenia. One-fifth were in remission. Low BMI correlated with sarcopenia. More patients with sarcopenia had disease flare. Screening for sarcopenia should be considered in patients with IBD.