Conversion disorder (CD) is a psychiatric disorder which can mimic organic disorders due to symptom similarities. It is characterized by the presence of one or more neurologic or vegetative symptoms that are usually triggered by stress. Therefore, medical diseases, neurological and psychiatric disorders should be considered in the differential diagnosis. We describe a case of a 12 year-old girl with type II citrullinemia that has been initially misdiagnosed as CD because of family attitude, secondary gains, and presence of symptoms such as clouding of consciousness and irritability. She has had no abnormal organic findings in previous exams. Metabolic disorders should also be considered in differential diagnosis of CD, even though they may be seen rarely.