A computer-based, self-administered, interactive questionnaire has been designed for interview and diagnosis of patients with functional headaches. Patients respond on a simple keyboard to a sequence of questions on a cathode-ray oscilloscope. The system selects pertinent questions depending on the patient's individual responses. The questionnaire included clinical symptoms, neurological manifestations, prior treatment, emotional factors, and personality problems. Upon completion, a computer-generated printed summary is presented for the clinical record. The system utilizes the acquired data to differentiate between common, classical, and cluster migraine, muscle contraction, and other types of headache. Computer diagnoses agreed with those of the physician in 36 of 50 patients. The automated interview saves physician's time, offers a data base for research, and provides a diagnostic aid for patients with functional headaches.