The purposes of this article are to describe the process of adapting an existing model to create a framework suitable for public health nursing (PHN) practice and to demonstrate how the resulting model can guide research for PHN practice. Using the PRECEDE (predisposing, reinforcing, and enabling causes in educational diagnosis and evaluation) model as a base, we synthesized concepts of health behavior, health education, health promotion/disease prevention, and program evaluation to develop a model for planning and evaluating aggregate-level PHN interventions to improve the use of the Early and Periodic Screening, Diagnosis, and Treatment Program (EPSDT) in rural North Carolina. The model provided the framework for identifying variables relevant to EPSDT use, designing interventions to improve use, and planning a research evaluation of the effectiveness, efficacy, and cost effectiveness of the interventions. This model, and the process used in adapting it for PHN practice, should be helpful for others investigating methods of reaching and bringing effective health-promotion/disease-prevention information to underserved, low-education members of minority groups.