INTRODUCTIONn: The Munchausen Syndrome by Proxy occurs when parents make a child believe he or she suffers from a disease while in fact this is not true. A medical diagnosis ruling out a possible disease of the child does not calm the parents down and only confirms--in their belief--the doctor's incompetence which in turn makes them seek a second opinion. This may be repeated over and over again and be accompanied by administration of medicines, overprotection, introducing a diet, limiting exercise as well as limiting motoric and mental development. OBJECTIVE Authors present diagnostic difficulties in diagnosing the Munchausen syndrome. METHODS A 6-year old girl was hospitalized for the first time at the Developmental Age Psychiatry and Psychotherapy Ward of the John Paul II Pediatric Center in Sosnowiec, Poland (until then she had received psychiatric treatment at the Center on an outpatient basis only). Medical history provided by her mother as well as supplied documents show numerous hospitalizations at Pediatric Wards since the girl was 6 weeks old due to intensified vomiting and frequent diarrheas. Since the age of 4, the girl has been provoking vomiting as well as temporarily refusing meals and liquids. CONCLUSIONS Authors present diagnostic difficulties in diagnosing the Munchausen syndrome mainly caused by discharging the patient from the Ward on her mother's request as well as non-specific nature of the symptoms.