A chart review study was conducted on 109 family practice patients with the complaint of chest pain. Overall and age-sex specific rates were established for chest pain of organic and of unproven etiology. Fifty percent of the chest pain was of unproven etiology after six months follow-up. The highest incidence rate of chest pain was in middle-aged males; they also had the highest incidence of chest pain of unproven etiology. For females, the highest rate of chest pain of unproven etiology was also in the 45 to 64-year age group. The greatest male-female differences for chest pain of unproven etiology were seen in the 15 to 24-year (female predominance) and the 25 to 44-year (male predominance) age groups. Patients with chest pain of unproven etiology had a significantly greater incidence of anxiety-depression than a control group (matched for age, sex, and practice) and a group of organic chest pain patients. Characteristics of the chest pain were also examined, but there were few differences in the description of the chest pain between the patients with chest pain of organic and unproven etiologies.