Introduction: Fahr syndrome is a rare phenomenon of idiopathic calcification of the basal gan-glia in the brain that is accompanied with psychiatric symptoms such as delusions, hallucina-tions, depression and neurological motor and cognitive deficits. This syndrome is acciden-tally diagnosed on brain CT scans of patients with mental disorders.

Case Report: Our patient was a 35 year old man with persecutory delusions, visual and auditory hallucinations admitted to Baharan hospital in Zahedan in 2012. On mental status examination, he showed persecutory delusions, psychomotor retardation, lack of eye and verbal contact, slow affection , depression, sleep and appetite disturbance and sexual dysfunction. IQ test revealed subnormal and MMPI proved psychopathology with schizoaf-fective symptoms. In paraclinical studies, symmetric and extensive calcification of brain structures was reported, Despite all laboratory indices such as serum calcium and phosphorus were within normal range.

Conclusion: According to his history, mental state examination and clinical evaluation the diagnosis of Fahr's syndrome was made. The patient was treated with olanzapine 1mg and citalopram 20mg daily. After three weeks of treatment, the patient’s communication, mood and cognitive status fairly improved ,his hallucinations resolved , and his delusions decreased.