A business-practice model is a guide, or toolkit, to assist managers and clinical pharmacy practitioners in the exploration, proposal, development and implementation of new clinical pharmacy services and/or the enhancement of existing services. This document was developed by the American College of Clinical Pharmacy Task Force on Ambulatory Practice to assist clinical pharmacy practitioners and administrators in the development of business-practice models for new and existing clinical pharmacy services in ambulatory settings. This document provides detailed instructions, examples, and resources on conducting a market assessment and a needs assessment, types of clinical services, operations, legal and regulatory issues, marketing and promotion, service development and exit plan, evaluation of service outcomes, and financial considerations in the development of a clinical pharmacy service in the ambulatory environment. Available literature is summarized, and an appendix provides valuable citations and resources. As ambulatory care practices continue to evolve, there will be increased knowledge of how to initiate and expand the services. This document is intended to serve as an essential resource to assist in the growth and development of clinical pharmacy services in the ambulatory environment.