Of intracranial physiological calcification, common calcification of pineal region, choroid plexus of lateral ventricles and of basal ganglia was examined based on the frequency of occurrence of age and sex and type of CT scanners. Consecutive cases of 2877 (1450 males and 1427 females) underwent plain CT scanning were studied. Pathological calcification was excluded from this study. Three types of CT scanners (SCN-200, Somatom 2 and TCT-10 A) were used. As a whole, calcification was shown in 67.7% in pineal region, 57.6% in choroid plexus of lateral ventricles and 7.5% in basal ganglia. First, we reported in detail the calcification of pineal region, in which calcification occurred most frequently. Calcification in pineal region had a close relation with age by increasing with aging. The youngest patient was 8 years old. There was a striking increase in number of patients aged from 10 to 39 years. There was a gradual increase in those aged over 40 years. Of patients aged from 70 to 79 years, calcification was found in 81.5%. The incidence was noted no changes in patients aged over 80 years. As for patients aged over 20 years, calcification was observed in 75.1% (82.6% males and 68.0% females). In patients aged from 20 to 79 years, the calcification was significantly higher in male than female. Although there was a different incidence of calcification examined by three types of CT scanners, it was not significant. There was no significant difference between thickness of 8 mm section and 10 mm.