RESUMEN
Patterns of attendance and referrals in hospitals and health centres in Riyadh region, Saudi Arabia, studied before and after implementing a referral system showed a 40.6% total decrease in patients attending hospital outpatient clinics; an 11.9% increase in patients attending primary health centres; a 19.2% increase in referrals; a 33.2% increase in patients attending emergency departments; and a 17.3% increase in inpatients. It is clear that the referral system has, and will have, an impact on primary and secondary health care services. In order to optimize positive and minimize negative aspects of this impact, communication between primary health centres and hospitals should be of high standard. Regular reviews and studies of referral systems are recommended