Development of foot-arching was studied on tread-prints of 639 male and 514 female members of 313 families dwelling in the Kwangju city of the Southern district, Korea. The subjects had used shoes except babies. Mukherjee's new approach was adopted for the objective quantification on indices of overall flatfootedness. The average degree of foot-arching in normal adults was nearly achieved by about eight years of age, and the index of flatfootedness had greatly changed from two years of age onwards when foot-arching started developing with the onset of walking. On the average, the bilateral and sexual differences in foot -arching were non-significant and the development of foot-arching might progress slightly faster in females. The frequency of individuals with flatfootedness or highly foot-arching was very high in affected sibships. Correlations of the index between fathers and sons(P.<0.01) and between fathers and daughters(P.<0.05) suggested an influence of paternal heredity on foot-arching.