Recognizing that school-based health centers are one of the most promising recent innovations to address the health and related needs of adolescents, this report provides information on these centers as a strategy to improve the access of adolescents to primary care. The report is intended to assist state and local Maternal and Child Health (MCH) policy makers, state and local health department personnel, administrators, and program managers in assessing the ability of school health centers (SHCs) to meet the primary care needs of adolescents. The development of SHCs is outlined and the defining elements of primary care are defined. Starfield's model of primary care is used as a conceptual framework to assess the strengths and weakness of SHCs as primary care sites for adolescents. Research findings on SHCs are summarized in a table delineating potential strengths and weaknesses with respect to the seven defining attributes of primary care: (1) first contact; (2) continuous; (3) comprehensive; (4) coordinated; (5) community-oriented; (6) family-centered; and (7) culturally-competent. Findings indicate that SHCs have many strengths, including elimination of access barriers; provision of a variety of services to meet adolescents' physical, mental, and social needs; successful coordination with managed care organizations; and use of creative ways to involve families. Weaknesses include restriction of operation time; high turnover; lack of evaluation research; and difficulties in coordinating care with other community providers. (Contains 49 references.) (KDFB)