Registered nurses (RN) participate in delivery of routine pediatric preventive care. This pilot study characterized variation in RN roles and overlap with other team roles.We conducted a pilot cross-sectional survey of RNs from an urban/suburban pediatric primary care network. RNs described tasks during preventive visits and other staff completing similar tasks. Health system data characterized office staffing, volume, and patient population. We assessed whether role overlap and time on key tasks was associated with office characteristics or staffing ratios.Twenty-three offices reported a mean ratio of RNs to physicians and nurse practitioners of 0.99 (range 0.62-1.33). Of tasks RNs completed during preventive care, health education overlapped most with physician/nurse practitioner roles (17 sites with overlap) and rooming patients overlapped most with medical assistant roles (20 sites with overlap). Across sites, RNs spent 9% of time on health education and 26% on rooming. Offices with more role overlap between RNs and physicians/nurse practitioners had higher RN to physician/nurse practitioner ratios (1.13 versus 0.86, t-test p-value 0.002). There was no association between role overlap and other office characteristics, or between RN time on key tasks and staffing ratios.RN staffing ratios varied twofold across offices. RNs spent more time on tasks that overlapped with medical assistant roles than tasks that overlapped with physician/nurse practitioner roles.Opportunities exist to optimize RN pediatric primary care roles, for example by delegating certain tasks. Optimization may reduce costs, while improving quality, patient experience, and staff satisfaction.