Effective physician-patient communication builds robust physician-patient relationships and reduces medical disputes. However, much is unknown about the differences that exist in the communication behaviors of physicians in different departments. Using a mixed-methods research approach, the researchers used Roter Interaction Analysis System to uncover the communication behaviors of internists, surgeons, family physicians, and emergency physicians at a regional hospital in Taiwan. Semi-structured interviews were conducted to collect the communication experiences of 20 physicians from the internal medicine, surgery, family medicine, and emergency departments. The characteristics were presented through descriptive statistics, bar charts, and dendrograms. Physician-patient communications consisted of four dimensions, 10 factors, and 31 behaviors. The characteristics are as follows: (1) Internists need to improve their overall performance in terms of physician-patient communication behaviors; (2) Surgeons performed well in building relationships through non-verbal methods; (3) Family physicians excelled in facilitation and patient activation. (4) Emergency physicians performed well in patient education and counseling. The characteristics of the aforementioned communication behaviors among internists, surgeons, family physicians, and emergency physicians can be used to construct indicators of physician-patient communication in each department and to develop patient-centered healthcare services in the future.