To understand trends in emergency medicine and interprofessional roles in delivering this care, we analyzed a 10-year period (1995-2004) by provider, patient characteristics, and diagnoses. The focus was on how doctors, physician assistants (PAs) and nurse practitioners (NPs) share emergency medicine visits. The National Hospital Ambulatory Medical Care Survey of over 1 billion "weighted" emergency room visits for 1995 to 2004 was analyzed. The majority of patients were female (53.2%); the mean age of all patients was 35.3 years old. By 2004, physicians were the provider of record for emergency visits at 92.6%, with PAs at 5.7% and NPs at 1.7%. Emergency visits increased for all three providers over the ten years with PA growth doubling during this same period. Medications were prescribed for three-quarters of the visits and were consistent in the mean number of prescriptions written across the three prescribers. No significant differences emerged when urban and rural settings were compared. Expansion of the roles and interprofessional care provided by NPs and PAs include increasing acceptance, clarification of legal and regulatory aspects of practice, shared roles, team approaches to shortages of fully-trained doctors, and the limitation of working hours of physician postgraduate trainees. The US forecast for emergency department visits is expected to outpace the growth of the population and the supply of emergency medicine providers. In view of an increasing emergency medical demand and a continuing shortage of physician personnel, policies are needed for workforce planning to meet the demand.