In this case report, an OCD patient, who had been followed up with psychotic disorder diagnosis and treated with depot and oral antipsychotics for 2 years, is going to be discussed. We suggested that, Parkinsonism symptoms occurred due to antipsychotics and we rearranged his medical treatment. After adding anti-obsessional medication to treatment and rearrange medications, symptoms and functionality improved greatly. Our case is a 36-years-old male. Two years ago, he had diagnosed as having psychotic disorder and treated with ECT, depot and oral antipsychotics. In spite of this treatment, in addition to his latter complaints, he presented extra complaints such as sexual obsessions and movement restrictions. He was hospitalized to our clinic. His physical examination was ordinary. In his neurological examination, there were movement restrictions and mask-like facial expression. His personal medical history was clear. At the time of mental state examination, his self-care was moderate; psychomotor activity was lowered. His mood and affect was restricted; partially anxious. His spontaneity and rate of speech were decreased and his tone of speech was monotonous. There was an overvalued idea such as somebody has bewitched him. His speed of thought was lowered and there was response time latency. There were sexual obsessions; and compulsions like praying and repeating words from inside. His memory examination was ordinary, except recalling. His ability of abstract thinking was partially conserved. His fund of knowledge and intelligence was coherent with his education. His insight was poor. The patient was diagnosed as having OCD and he scored 45 points from Yale-Brown Obsessive Compulsive Scale (YBOC-S). His Mini Mental State Examination score was 24. Antipsychotic doses that he was receiving were reduced and the treatment was rearranged as risperidone 2 mg/day, şuvoxamine 100 mg/day, and clonazepam 2 mg/day. Neurology consultation was made for Parkinsonism symptoms and his brain MRI and EEG findings were found to be in normal range. Movement restriction, rigidity and mask-like face expression symptoms were thought to be associated with the use of depot antipsychotics. With regard to this, antipsychotic doses were reduced and stopped gradually. Lithium was added to treatment as an augmentation. In his clinic follow-ups, his obsessions and sociality were improved and he started to express his obsessions with more ease. Parkinsonism symptoms were reduced and his insight of disease was improved. In the repetition rating of YBOC-S, he scored 30 points (his first score was 45). The patient, whose psychotic symptoms were disappeared and affective interaction improved, discharged from hospital with şuvoxamine 200 mg/day, clonazepam 2 mg/day, lithium 600 mg/day, vitamin-E 400 mg/day and omega-3 1000 mg/day. Parkinsonism is a commonly seen side effect in patients using antipsychotic medication. OCD patients, whose insight are poor and present psychotic symptoms can be misdiagnosed in polyclinics and can be administered a high dose of antipsychotics. In these situations, this may contribute to the worsening of the prognosis and the functionality of the