Calprotectin is a protein found in the cytosol of inflammatory cells and is a marker of the presence and the degree of inflammation in the bowel system. Calprotectin in feces has great diagnostic value in the matter of inflammatory bowel disease (IBD). In feces, the protein is stable up to seven days, and since the protein can easily be measured with an ELISA, the use of fecal calprotectin (FC) means no invasive measures. For adults and children over 4 years, a cut-off level of 50 mg/kg has been well established for diagnostic purposes. Because previous studies have proven that children under the age of four in general have higher FC values than older children and adults, there is a need for a cut-off level for this age group. In order to establish that, the normal values for FC in children from 0-4 years were investigated. Some 75 stool samples from healthy children were collected and the levels of FC were analyzed. The results were compared to 157 pediatric cases where FC analysis had been performed for diagnostic purposes. As a result, three cut-off levels were established based on the 97.5% percentiles of FC in different age groups: 538 mg/kg (1 < 6 months), 214 mg/kg (6 months < 3 years) and 75 mg/kg (3 < 4 years).