This study was attempted to investigate the cohort difference in physical growth and development of senior high school boys and girls. Those who enrolled in K senior high school of T city as freshmen from 1970 through 1974 were tested longitudinally for three years up to their graduation with 12 sports test items and 4 physique items. Thus, five of longitudinal deta respectively for the boys and girls were obtained representing the classes enrolled in each year from 1970 through 1974. Sample size of each year was not always equal, but total sizes were 892 for boys and 1005 for girls. The two-way analysis of variance was utilized for the quantitative evaluation of the cohort differences in physical growth and development, and furthermore, the growth and development patterns expressed qualitatively as increase, unchange and decrease were compared in each growth and developmental attribute between different enrollment years. Then, the following results were obtained. 1) No significant differences were found in all items of boys and girls between different enrollment years and grade. 2) In boys, of four items which showed complete agreement in their growth and developmental patterns between different enrollment years, three; e. g. side steo, trunk extension and 50m dash, showed an increasing tendency during three-years of senior high school. In girls, however, such complete agreement of growth and development pattern as showed in boys was not found. 3) Back strength, standing height, 1,500m endurance run in boys, and standing height, body weight, trunk flexion and 50m dash in girls showed comparatively high degree of agreement in their growth and deve1opmental patterns between different enrollment years. 4) It was suggested that side step, trunk extension. trunk flexion and 50m dash showed no difference in their growth and developmental pattern that were expressed qualitative1y, but cohort difference should be taken into consideration to analyze the physical growth and development quantitatively.