Despite the recognized importance of school nurses, the ratios of nurse to pupil are insufficient in many states across the country. The purpose of this study was to describe school nurse-to-pupil ratios by state and to statistically identify factors that may influence these ratios. Funding per pupil unit in general and support services and laws mandating school nurse ratios were some of the factors found to be associated with school ratios. Although the study has significant limitations, this is the first study of its kind to examine factors associated with ratios using secondary databases that are state-specific. Data such as this provide a context for studying those factors potentially influencing ratios. Further studies are needed to explore the numerous potential determinants described in the literature. Once key factors are identified, school nurses can effectively focus their efforts to lower school nurse-pupil ratios. (Contains 4 tables.)