Optimal communication between primary care physicians and consultants includes transfer of relevant clinical information, including the patient's perspectives and values, and provides a means of collaboration to provide meaningful and health-promoting interventions. Communication difficulties arise because of lack of time, lack of clarity about the reason for referral, patient self-referral, and unclear follow-up plans. Also, primary care physicians and consultants may have different core values and may have little day-to-day contact with each other. Poor communication leads to disruptions in continuity of care, delayed diagnoses, unnecessary testing, and iatrogenic complications. Changes in the health care system offer the opportunity for improved collaboration between physicians by creating smaller administrative units within large health care systems that facilitate contact between primary care physicians and consultants; incorporation of discussions of uncertainty, patient preferences, and values into referral letters; adoption of a friendlier consultant letter format; and the improvement of the transfer of clinical data.