Background/Aim: Metabolic syndrome (MetS) is a clinical condition characterized by central obesity, elevated triglycerides, low-high density lipoproteins, impaired fasting glucose, and hypertension. There is insufficient data on the prevalence of MetS in patients with inflammatory bowel disease (IBD). This study sought to determine the prevalence of MetS in a Turkish cohort of patients with IBD and the association between insulin resistance (IR) and the MetS parameters, in this population. Patients and Methods: A total of 177 patients over 18 years of age (62 with Crohn′s disease (CD) and 115 with ulcerative colitis (UC)) were enrolled in the study. The presence of at least three criteria of the International Diabetes Federation (IDF) was accepted for the diagnosis of MetS. The Homeostasis Model Assessment (HOMA) was used to determine IR. HOMA values < 1 were considered normal and values > 2.5 indicated a high probability of IR. Results: MetS frequency was higher in patients n=34 (29.5%) with UC than in patients n=11 (17.7%) with CD (P < 0.01). MetS was detected in 12 of the 117 patients (10.3%) with IBD, under 45 years of age, and in 33 of 60 patients (55%) over 45 years of age. HOMA value in n=31 patients (27%) with UC was > 2.5. Body mass index, insulin (P < 0.001), waist circumference, fasting plasma glucose, leukocyte count (P < 0.01), triglycerides, C-reactive protein, and uric acid values (P < 0.05) were significantly higher in UC patients with IR than those without IR. Conclusion: Frequent occurrence of MS with increasing age in IBD, particularly in UC, showed the importance of early diagnosis and treatment of cardiovascular disease risk factors in the long-term follow-up of these diseases.