We reviewed computerized tomograms (CT) for basal ganglia and dentate nucleus calcifications in 79 patients with Parkinson's disease (PD), 54 patients with Alzheimer's disease (AD) and 109 controls aged 50 or more. When it was determined, no patient had disturbances in calcium metabolism. We found: (1) 30 subjects out of 242 (12.3%) with calcification located within the lenticular nucleus in 28. (2) Calcifications were unilateral in 11 and asymmetric in 11. (3) The prevalence of calcifications was 21.5% in PD, 9.2% in AD and 7.3% in controls and were significantly more severe in PD than in C and AD (P less than 0.02). (4) PD patients with calcifications were clinically indistinguishable from those without calcification. (5) Calcifications within the basal ganglia were not associated with a levodopa-resistance. We suggest the basal ganglia calcifications are more frequent in PD, but we cannot explain why, since post-synaptic lesions have never been showed in PD.