Prescribing medicine over the telephone was studied during a two-month period in a two-physician fee-for-service private family practice. Of 1,264 telephone calls, 392 (31.0%) resulted in a medication prescription. Of these calls, 176 (44.9%) were for refills of previously prescribed medicines. The most common drugs for new telephone prescriptions were decongestants/antihistamines/antitussives, antibiotics, and pain medications. Medicines were more likely to be prescribed via telephone for the diagnoses of upper respiratory infections, headache, low-back pain, or bronchitis. A patient was more likely than expected to get a telephone prescription for new problems when a message was left in the office for the physician by a caller other than the patient's son or daughter.