The purposes of this study were to investigate the quality (structure and process) of home-based day care and center-based day care, and to examine socio-emotional development among infants who were in both types of day care. The subjects of this study were 101 infants who were in home-based day care and 181 infants who were in center-based day care. The measurements were socio-emotional development scale and assessment scales for day care programs. Results indicated that, first, home-based day care did not significantly differ from center-based day care in terms of structure. Second, home-based day care were, to some degree, significantly different from center-based day care in the process： home-based day care had better play environment and play activities than did center-band day care. Lastly, there were significant differences in socio-emotional development among infants according to the type of day care： infants in home-based day care were more independent to their teacher and felt more secure in child care homes than was true for the infants in center-based day care.