Munchausen syndrome is a psychiatric disorder characterised by the deliberate imitation of symptoms of physical or psychiatric illness by the patient in order to convince others and health professionals that they have a disease. The patient often exhibits a specific pattern of behaviour, such as lying about their symptoms and influencing test results to prove the presence of symptoms. Munchausen Syndrome by Proxy is similar to Munchausen Syndrome, but the clinical scenario is presented not by the child himself or herself but by the adult responsible for his/her care. This is a type of child abuse because it exposes the child to unnecessary medical procedures. The most important step in making a diagnosis for both Munchausen syndrome and Munchasen syndrome by Proxy is to suspect. In this report was aimed to raise physicians' awareness about Munchausen syndrome, a condition that can be overlooked and rarely diagnosed in pediatric cases. Case Report: A fifteen-year-old girl presented with haematemesis. The site and cause of haemorrhage could not be found by endoscopy and other medical procedures. Munchausen syndrome was diagnosed after it was discovered that the patient was simulating hematemesis by taking venous blood from his arm with a syringe and collecting it in his mouth. Conclusions: Suspicion is a significant factor in the diagnosis of Munchausen syndrome. It is important that medical doctors and other healthcare professionals enhance their knowledge and comprehension of Munchausen syndrome.