ABSTRACT BACKGROUND: Data regarding the prevalence of anemia in inflammatory bowel disease (IBD) patients are scarce in Brazil. Anemia and iron deficiency anemia have been known to cause significant functional impairment, lower quality of life, and higher morbidity and mortality and may be correlated with an impact on the cost of treatment. OBJECTIVE: The aim of this study was to estimate the prevalence and risk factors for anemia and iron deficiency anemia in patients with IBD in a tertiary IBD unit in Southeast Brazil. METHODS: We conducted an Institutional Review Board-approved retrospective analysis of an adult IBD cohort (IBD Unit, Ribeirão Preto Medical School, University of São Paulo, Brazil) consisting of 579 patients between January 2014 and July 2018. Clinicoepidemiological data, hemoglobin measurements and serum ferritin were extracted from electronic medical records. Anemia prevalence was calculated among ulcerative colitis (UC) and Crohn’s disease (CD) phenotypes. Risk factors for anemia were also calculated. RESULTS: A total of 529 (91%) patients had complete blood counts available in their medical records. Only 35.5% of IBD patients were fully screened for anemia. The prevalence of anemia in IBD patients was 24.6% (29.1% in CD and 19.1% in UC, P=0.008). The anemia was moderate to severe in 16.9% (19.8% in CD and 11.4% in UC, P=0.34). The prevalence of iron deficiency was 52.3% (53.6% in CD and 51.2% in UC, P=0.95). Anemia of chronic disease was present in 14.1% of IBD patients. A total of 53.8% of patients with anemia were in clinical remission. CD was associated with an increased prevalence of anemia (P=0.008; OR=1.76; CI 95% =1.16-2.66) compared to UC. The penetrant disease phenotype in CD was associated with a lower risk of anemia (P<0.0001; OR=0.25; CI 95% =0.14-0.43). Active disease compared to the disease in clinical remission was associated with an increased risk of anemia (P=0.0003; OR=2.61; CI 95% =1.56-4.36) in CD. The presence of anemia was less frequent in patients with CD who underwent surgical bowel resection compared to those who did not undergo surgery (P<0.0001; OR=0.24; CI 95% =0.14-0.40). No differences in anemia prevalence were observed regarding CD localization, age at diagnosis, UC extension or biological therapy (P>0.05). CONCLUSION: Despite the low levels of full screening, anemia and iron deficiency anemia were common manifestations of IBD. CD was associated with an increased risk of anemia, especially with active disease. In addition, patients with CD who underwent surgical bowel resection and penetrant disease phenotype in CD were associated with lower risk of anemia.