REM Behavior Disorder (RBD) is seen in elderly population mostly. Its prevalence is unknown but the disease was reported in 0.38% of overall population and in 0.50% of elderly population. One third of newly diagnosed Parkinson’s patients, 47% of overall Parkinson’s patients and 90% of multiple system atrophy patients diagnosed as RBD. RBD is a chronic, progressive sleep disorder and its frequency or severity changes over time. Fahr disease (FD) most common clinical signs are Parkinsonism, dystonia, tremor, chore, ataxia, dementia and affective disorders. Etiopathogenesis of RBD and FD are still unknown. Our patient presented with FD with the calcification in basal ganglions before Parkinson’s disease manifested. We aimed to underline the importance of FD in the differential diagnosis of RBD and RBD must be considered and kept in mind during the clinical course of FD.