The role of the telephone in medical practice is important, but often problematic. Mistakes in telephone diagnosis and triage can have severe consequences. An effective office system can reduce liability risks, and in some cases telephone contact can substitute for office visits. Internists feel unprepared to provide telephone care. Therefore, residency education needs to focus on documentation, consultant availability, and performance feedback. Research should focus on improving outcomes, reimbursement issues, and technologic advances. This article describes internists' telephone interactions with ambulatory patients, preparation for telephone medicine, and aspects of office telephone systems and makes comparisons with other primary care fields.