Iron deficiency anemia (IDA) is the most common type of anemic disorder, accounting for 41.5% of cases. According to the WHO, the clear lack of iron is fixed at 30% of the world's population, but 2 times more likely to observe a latent iron deficiency. The article discusses the diagnosis of iron deficiency anemia in the practice of a gastroenterologist. A list of diseases of the gastrointestinal tract and algorithms for detecting iron deficiency anemia in them are presented.