This study investigates the effects of a brief training programme on the communication skills of doctors in ambulatory care settings in Trinidad and Tobago. Evaluation of doctor performance is based on analysis of audiotapes of doctors with their patients during routine clinic visits and on patient satisfaction ratings. A pre-test/post-test quasi-experimental study design was used to evaluate the effects of exposure to the training programme. Doctors were assigned to groups based on voluntary participation in the programme. Audiotapes of the 15 participating doctors (nine trained and six control) with 75 patients at baseline and 71 patients at the post-training assessment were used in this analysis. The audiotapes were content-coded using the Roter Interaction Analysis System (RIAS). Doctors trained in communication skills used significantly more target skills post-training than their untrained colleagues. Trained doctors used more facilitations in their visits and more open-ended questions than other doctors. There was also a trend towards more emotional talk, and more close-ended questions. Patients of trained doctors talked more overall, gave more information to their doctors and tended to use more positive talk compared to other patients. Trained doctors were judged as sounding more interested and friendly, while patients of trained doctors were judged as sounding more dominant, responsive and friendly than patients of untrained doctors. Consistent with these communication differences, patient satisfaction tended to be higher in visits of trained doctors.