BACKGROUND: There is no single reliable marker of iron homeostasis in inflammatory bowel disease. AIMS: To determine diagnostic usefulness of soluble transferrin receptor and soluble transferrin receptor/log ferritin index in iron deficiency anemia in children with inflammatory bowel disease. METHODS: We assessed soluble transferrin receptor in serum and calculated soluble transferrin receptor/log ferritin index in 75 children with inflammatory bowel disease. Diagnostic ability to identify iron deficiency anemia was examined by receiver operating characteristic analysis. RESULTS: Study group comprised 27 cases of iron deficiency anemia, 6 anemia of chronic disease with iron deficiency, 5 anemia of chronic disease. Soluble transferrin receptor was significantly increased in children with iron deficiency anemia (median: 1.63 mug/ml) compared to non-anemic children (median: 1.02 mug/ml). Soluble transferrin receptor/log ferritin index was significantly higher in iron deficiency anemia (median: 1.76) than in anemia of chronic disease (median: 0.55), anemia of chronic disease with iron deficiency (median: 0.68) or patients without anemia (median: 0.72). Soluble transferrin receptor and its index were not correlated with disease activity or inflammatory markers. Diagnostic power for soluble transferrin receptor/log ferritin index (0.864) was superior to soluble transferrin receptor (0.768) in iron deficiency anemia recognition. CONCLUSION: Soluble transferrin receptor/log ferritin index has better diagnostic utility than soluble transferrin receptor for iron deficiency anemia detection in pediatric inflammatory bowel disease.