Idiopathic Parkinson Disease (PD) is a motor system disease, which is resulted in loss of dopaminergic neurons in substantia nigra and clinically demonstrated by resting tremor, bradykinesia, rigidity, and postural reşex disturbance. Levodopa, COMT enzyme inhibitors, MAO inhibitors, amantadine, anticholinergics are used for treatment of PD. Recently; atypical psychoticantipsychotic drugs are used for resistant cases and psychotic symptoms that are potentially caused by PD treatment. It is aimed to report a a nonresponder case to antiparkinson treatment and whose psychotic symptoms have not regressed with other atypical antipsychotics but with clozapine. A 67-year-old male, who lives with his family. He applied neurology policlinic with symptoms such bradykinesia, akinesia, tremor, walking difficulty, suspicious thoughts, thought of being followed and harmed by people. The patient has had suspicious thoughts for 10 years, whereas tremor and bradykinesia at right hand for 7.5 years. Levodopa-carbidopa-entacapone treatment was started as first line treatment in an external clinic. The patient’s bradykinesia started to decrease but amantadine was added on the existing treatment due to contractions around mouth and right toe. Rasagiline and ropirinole was added to treatment 2 years before but the result was limited. The patient was treated at psychiatry clinic for persecution and reference delusions at 2011 and discharged on aripiprazole 30 mg/day. The patient was hospitalized to neurology clinic in September 2012 due to onset of bradykinesia and his treatment was redesigned as levodopa-carbidopa-entacapone 750mg/day, rasagiline 1mg/day, ropirinole 14mg/day and quetiapine 100mg/day. The patient’s neurological picture under this treatment involved resting tremor at upper extremities, 2+ rigidity at right upper extremity, 1+ rigidity at left upper extremity, 1+ bradykinesia at both upper extremities and bradimimia. He had ortostatic hypotension. The patient was transferred to psychiatry clinic due to paranoid and persecutive delusions had appeared and olanzapine 5 mg/day was started and its dose was increased to 10 mg/day but delusions didn’t regress and motor disfunctions worsened. Then olanzapine was stopped and clozapine was started. The patient was transferred to neurology clinic again due to regression of psyhcotic symptoms. The patient was discharged with bradykinesia and akinesia on levodopa-benserazide 1500mg/day and clozapine 50mg/day. The patient was stabile during his policlinic controls. The patient’s suspicious thoughts and persecutive delusions started 10 years before and increased in time. Bradykinesia started 4 years ago. About 1% of patients with newly diagnosed PD have psychotic symptoms in recent studies. Research proved that clozapine was useful for Parkinson’s patient with resistant visual hallucinations and motor symptoms were deteriorated by using olanzapine and quetiapine. The researchers also proved that clozapine is the most effective treatment in 10-year survey of 32 Parkinson’s patients with psychotic symptoms.