A slowly upsloping ST segment depression is an abnormal, and a rapidly upsloping ST segment depression is a normal exercise ECG response. We investigated the agreement of expert physicians on the visual classification of the ST segment depression, and compared the (majority) vote with the computer-generated ST slope. A total of 206 exercise ECG leads with an amplitude of the ST segment depression ≥0.15 mV and a ST segment slope ≥0.5 mVs<sup>–1</sup> were evaluated. All three interpreters agreed in 68 cases, two agreed in 123 cases, and all disagreed in 15 cases. Intraobserver agreement was 61%. The ST segment slope was significantly (p < 0.001) greater in leads generally interpreted as rapidly upsloping (n = 38; 2.1 ± 0.8 mVs<sup>–1</sup>), than in those interpreted as slowly upsloping (n 121; 1.3 ± 0.6 mVs<sup>–1</sup>) or horizontal (n = 32; 1.1 ± 0.4 mVs<sup>–1</sup>), although there was some overlap. Thus, standardization of the computer-assisted exercise ECG interpretation should be continued.