We present here a framework of core components of an ambulatory care computing environment, based on clinical and functional needs and workflow scenarios. We have established this framework through the use of two study devices: a vision of the clinical office of the future, and a survey of possible computer applications, both designed to help clinicians and practice directors communicate their information needs to systems designers. Clinicians prioritize applications based on strategic and practice goals: support for clinical users' workflow, improved quality of care, reduced cost of care, and the ability to measure performance and status. By reorganizing the needed functionality from a clinical viewpoint into a technical viewpoint, we are able to identify core information components for systems design. Based on this analysis, information needs in the ambulatory environment can be divided into five primary functions: patient data retrieval, documentation, communication, knowledge resources, and aggregate reporting. Three other fundamental processes--knowledge-based interventions, information integration, and confidentiality--run through all of these front-line functions. Component applications and data structures built with this framework in mind will afford a maximum combination of functionality and flexibility to handle future changes in the clinical environment.