Abstract Background Anemia is one of the most common extraintestinal manifestations in patients with inflammatory bowel disease (IBD) at diagnosis. Studies have shown that anemia was associated with low levels of quality of life, which improves with the correction of anemia in adults. Recent data have shown an increase in the incidence and severity of pediatric IBD. Aims To investigate the prevalence of anemia in children at diagnosis of IBD and the trends in the past decade. The secondary aim was to investigate the associations between hemoglobin (Hb) levels and disease characteristics. Methods Eligible patients (age ≤18 years, diagnosed with IBD from 2009 to 2018) were retrospectively identified through our IBD database. Disease localization and phenotype were defined according to the Paris Classification of IBD. Anemia was defined by Hb levels according to WHO targets. The annual prevalence of anemia was calculated according to subtype (inflammatory vs iron deficiency). The Pediatric Crohn’s Disease Activity Index (PCDAI) and the Pediatric Ulcerative Colitis Activity Index (PUCAI) were used to assess the disease severity at diagnosis. Results We included 887 patients (439 females), mean (SD) age of 13.1 (3.4) years. Of these, 519 (58.5%) were identified with anemia within 30 days of diagnosis. The median (IQR) Hb level was 108 (98 -114) g/dL. Severe anemia (< 70 g/dL) was present in 1.8 % of patients. The prevalence of anemia at diagnosis remained relatively stable ranging from 60.2% in 2009 to 60.4% in 2018. The annual proportion of inflammatory vs iron-deficiency anemia is displayed in figure 1. Anemia was more prevalent in Crohn’s disease (CD) (62.2%) than Ulcerative colitis (UC) (57.9%) or IBD-unclassified (39.6%). The disease severity scores were higher in those with anemia. The median (IQR) PCDAI and PUCAI were respectively 37.5 (27.5–47.5) and 55.0 (40.0–65.0) in the anemic group as compared to 27.5 (20.0–37.50) and 35.0 (25.0–55.0) in the non-anemic group; P<0.0001. Patients with anemia had a lower BMI z-score [median (IQR) -0.84 (-1.84 - 0.08)] than the non-anemic patients [median (IQR) -0.38 (-1.21 - 0.43)]; P<0.001. The prevalence of anemia correlated significantly with disease location: upper intestinal involvement [L4a(67.7%) L4b(63.6%) L4aL4b(60.7%) none (52.8%)] P = 0.024 for CD; for UC [E1(21.1%) E2(44.4%) E3(75.0%) E4 (71.1%)] P<0.0001. A moderate correlation was found between Hb levels and C-reactive protein (r= -0.312, 95% CI: -0.378 to -0.243, P<0.0001). Conclusions Anemia remains a prevalent symptom in pediatric patients with IBD, and it is correlated with the extent of intestinal involvement and disease severity. The impact of anemia at Diagnosis and during follow-up on the levels of quality of life and physical activity is currently under investigation. Funding Agencies None