The purposes of this study were : (1) to compare music aptitude scores of two different groups of Korean elementary students who were enrolled in the two elementary schools which had different socio-economic backgrounds (2) to investigate the differences of musical environment of the two groups ; and (3) to compare the effects of the different musical environments on the development of music aptitude. This study investigated two groups of fourth graders enrolled in the two elementary schools. Group one(n=160) consisted of the whole fourth graders at a school located in the central part of Seoul. Group two(n=262) consisted of the whole fourth graders at another school located in the area of Seoul where most of the residents were associated with the socio-economically low class. Based on the analysis of the data collected for the study, the following conclusions were drawn : (1) The scores of the music aptitude test(IMMA) of the two groups indicated that there were statistically significant differences between the two groups(p<0.05) in terms of music aptitude. This result supports the hypothesis that the environmental factors are related to the development of music aptitude. (2) The analysis of the survey which were designed to gather information on various musical environmental factors of the groups showed a very consistent tendency. That is, group one had better musical environments than group two in all of the nine survey items. This result, in turn, showed a clear relationship between the musical environment and the development of music aptitude; (3) The fact that the music aptitude scores of group two were higher than those of group two and that group one had better musical environments than group two indicate musically rich environments are one of the important contributing factors to the development of music aptitude.