As a basic study for the planning of infants' clothes, the relationship between morphological growth and functional development of infants was analyzed using questionnaire data collected longitudinally on subjects from birth to 3 years old. The survey was conducted in October 1988. The data of 114 males and 113 females were used in this study. The main results are as follows : 1) Principal component analysis shows that there are six components which form the growth and development of infants. Three components explain growth periods and the other three explain developmental stages. The periods and stages correspond with each other. 2) The relationship between growth patterns of weight or height and the time of functional development is recognized to a certain extent, that is, infants who obtain consistently superior growth develop sooner functionally. 3) Considering the construction of infants' clothes vis a vis functional development, baby dresses are suitable during the first period of growth, overalls during the second and separates during the third. The sizes and constructions of infants' clothes on the market are reasonable. From a consumer's standpoint, it is advisable to buy the appropriate sizes of infants' clothes after considering the season and the growth stage.