The purpose of this study was twofold; to investigate the relationships between the musical development of two- and three-year-old girls and their mothers' musical backgrounds and the music in their home environments; and to investigate the significance of the differences in the musical development of two- and three-year-old girls with reference to their socio-economic status (SES) and ethnicity. The relationships between the musical development of all subjects and music in the home environment were positive, rendering correlation coefficients that were statistically significant. These statistical inferences indicated that the musical home environment (the product of the mother, the father, and other adults, and the availability of musical items and activities) has the strongest relationship to the musical development of the young child. This influence begins before the age of two and continues during the third year. It was also hypothesized that there would be a significant difference in the musical development of the two- and three- year- old girls with reference to SES and ethnicity. Analysis of variance was employed to ascertain these differences. The subjects remained in age groups and were statistically regrouped by SES and ethnicity for these analyses. From the inferences rendered by these analyses, neither SES nor ethnicity made statistically significant differences in the musical development of these young girls.