Collaboration and communication between team members are key determinants of safety culture, but these concepts have thus far been better studied in the inpatient setting than in ambulatory care. In this study, the Safety Attitudes Questionnaire was used to measure teamwork between nurses, pharmacists, and physicians in four outpatient clinics. While nurses and physicians appeared to work well together, problems were identified with pharmacists' interactions with both nurses and physicians. Based on this finding, the authors suggest that teamwork training interventions in the outpatient setting should focus on these interprofessional interactions. A Patient Safety Primer discusses these and other issues pertaining to ambulatory patient safety.