This article describes the design and evaluation of a patient-instructor (PI) program that was developed to teach and assess dental student communication skills with patients, with an emphasis on cross-cultural patient encounters. The PIs were individuals from the community trained to portray specific simulated patients. One hundred eighteen dental students (three graduating classes) completed two half-day rotations that occurred in the junior year; seventy-nine of those students (two graduating classes) also completed a third rotation that occurred in the senior year. On each rotation, students worked with several simulated patients in mock clinic appointments. PIs used a standardized rating scale and case-specific content checklists to assess students' ability to elicit and provide essential information. Across counterbalanced cases, students improved as they progressed through encounters. Rate of improvement varied by rotation, but students improved most during their first rotation. Overall performance was best on the final rotation. Qualitative review of content checklist items indicated areas of strengths and weaknesses in communication regarding medical, dental, psychosocial, and cultural content. Results can direct curriculum changes to improve communication skills. Future research should address the effects of the PI program on students' diversity-related attitudes and behaviors.