Telephone nursing (TpN) care is delivered in a wide range of settings and provides a variety of services to individuals and populations across the age span. Although a viable specialty practice, there is little evidence regarding how the process of care delivery contributes to successful outcomes. To study the effects of TpN care, and to develop appropriate clinical and education interventions, a solid understanding of the process is needed. This study utilized grounded theory method to identify and describe the core concepts of the TpN process, the relationships among these concepts, and the factors influencing the process. Study findings were validated through peer and participant review. Based on interviews with ten telephone nurses from four sites, the following components were identified and organized into a conceptual model of the TpN process. The process generally proceeds through three phases, gathering information to cognitive processing to output. Throughout these phases, the nurse engages in a goal oriented parallel process focusing on both explicit (e.g., verbal, physical) and implicit (non-verbal, contextual) dimensions. Inherent to this parallel process is a two-way interpreting process in which information from the caller is translated into health care language for processing and then health care information is translated back into the language of the caller to identify and meet their needs. Factors influencing the process include prioritization and the level of complexity of the call, resources of the nurse and the organization, and the nurse's desire for validation of the service and the appropriateness of the output. The model highlights the need for research further delineating how implicit information is gathered and processed and how it influences output. Research is also needed on the value of implicit output and on the effects of feedback regarding output on nurse performance and satisfaction. The model suggests that more nursing education should be focused on the sub-processes within the three phases, the interpreting process, and implicit aspects of the process. Finally, the model suggests that formal feedback regarding the quality of call output should be provided and the value of implicit nursing output should be recognized.