Background/Aims: Patients with ulcerative colitis (UC) are at increased risk of colorectal cancer (CRC). High-grade dysplasia (HGD) andlow-grade dysplasia (LGD) are premalignant conditions. The aim of this study is to evaluate the risk of CRC/dysplasia in patients withUC, and the related risk factors.Materials and Methods: Medical records of 1659 patients dating between 1993 and 2016 were scanned from an inflammatory boweldisease database. A total of 801 patients with UC who underwent at least one colonoscopic procedure with at least 1-year follow-upperiod were included in the study. Clinical, endoscopic, and histopathological data were assessed.Results: The mean disease duration was 6.7±6.6 years. The total disease duration was 5334 person-years duration (pyd), and 34% ofpatients had the disease for 8 years or longer. The prevalence of UC-associated CRC was 0.7%, and the prevalence of dysplasia was0.85%. The overall incidence of CRC was determined to be 1.1/1000 pyd. The cumulative risk of CRC was 0.3% at 10 years, 1.3% at 20years, and 5.9% at 30 years. The Cox regression analysis indicated that primary sclerosing cholangitis (HR:13.677, 95% CI:2.6-70.8,p=0.012) was an independent risk factor for developing UC-associated CRC.Conclusion: This study underlined the low risk of CRC and dysplasia in patients with UC in a tertiary referral center in the western part ofTurkey. Primary sclerosing cholangitis was found to be the most important risk factor for the development of CRC in patients with UC.Identification of risk factors is important to categorize patients into subgroups to know which patients will require frequent surveillance.