A computer program for interpreting the adult 12-lead electrocardiogram has been evaluated. Four thousand electrocardiograms were used in the design of the program which was based on the diagnostic logic used in clinical electrocardiographic interpretation. An evaluation of the program so designed was conducted on 1435 other records, 1008 of which were abnormal. Ninety-seven percent of all records were correctly classified by the computer as either normal or abnormal. Ninety-four percent of all contour abnormality statements made were correct and only 6% of contour abnormality statements were omitted. Ninety-three percent of the normal electrocardiograms were correctly analyzed with most errors consisting of minor ST- and T-wave changes. Of the abnormal tracings, 1.2% were called normal. Eighty-two percent of all 1435 records had a completely acceptable computer interpretation. © 1972.