The purpose of the present study was to investigate the development of infants' grouping concepts. In this study, three types of grouping concepts were used nominal concept, contiguity concept, and perceptional concept. In Experiment 1, we measured infants' ability to utilize grouping concepts, and in Experiment 2, we analyzed the relationship between the most preferred concept and the ability to utilize concepts. Our results showed that in younger infants the most preferred concept was largely determined by their ability to utilize concepts, but in older infants the most preferred concept implied their conceptual preference.