Clinical estimation of gestational age at birth has been applied to 181 newborn infants who were born at Ewha Womans University Hospital from July to September 1979. Authors used neurologic examination based on evalution of passive tone, active tone and primary reflexes in order to estimate the gestational age, 1) Correlation coefficient between gestational age calculated from last menstrual period and clinical estimation of gestational age used in this study was 0.833 and regression formula was Y = 0.741+10.27. 2) There was no stastically significant difference in correlation coefficient between S.G.A, A.G.A., and I.G.A. groups. 3) Neurologic examination is objective and reproducible for estimation of gestational age in newborn infants.