A systematic sampling of prescriptions from primary care centers in the Al-Baha region of Saudi Arabia was analyzed to determine the patterns of drug prescribing and the compliance of practicing physicians in these centers with the essential drug list issued by the Ministry of Health. The average number of drugs per prescription was 2.3 +/- 0.7 of which 86.5 percent of the prescriptions contained two to three drugs. In 53.7 percent of the prescriptions no duration for treatment was specific and 96.5 percent of the prescriptions did not indicate drug strength. The study showed that analgesics and vitamins were the two most common classes of drug prescriptions in the centers and that 18.6 percent of prescribed drugs were not from the allowed list of drugs. The causes of polypharmacy and noncompliance with the limited list are discussed with emphasis on the essential drug list as a method of rationalizing prescribing in primary healthcare.