Aim: In this study, the correlation of faecal calprotectin (FC) levels with endoscopic and histopathological findings was evaluated in children who underwent upper gastrointestinal system (UGIS) endoscopy. Materials and Methods: The patients aged 4-18 years admitted to our endoscopy unit were included in this study. Faecal samples were collected on the day participants presented for the study. A calprotectin assay was performed on the faecal samples usingenzyme-linked immunosorbent assay kits. FC levels were compared with those of children with normal histopathology.