To assess the power of Stroop's color-word test to induce cardiovascular arousal in cardiac patients, 10 postinfarct patients underwent Stroop's test, as well as the mental arithmetic test, which was assumed to be the gold standard. Both stressors induced significant increases in heart rate and blood pressure; the differences between these increases were not statistically significant. Stroop's test is a useful alternative to the mental arithmetic test in the study of cardiovascular responses to mental stress.