The intent of this study is to investigate the current situations and planning implications of elementary schools in urban housing blocks, and to propose the planning and design guidelines for them. The premise of this research is that an elementary school should function as a communal facility, shared by its community, so called open-school. 32 schools in three new towns were selected as sample cases and they were closely surveyed in terms of their site planning issues in residential blocks, and three sample open-elementary schools were analyzed in a comparative manner for finding their roles and functional fulfillment as a communal facility in the neighborhoods. Based on the findings, several planning principles and design techniques or devices are suggested for the utilization of elementary schools by local residents, mainly making issues of location, relationship to other facilities and open spaces in residential blocks, access, apartment layout, school building and outdoor spaces, and open program.