Noninvasive techniques available for measuring cardiovascular effects of drugs are reviewed. The high-speed, high-gain surface electrocardiogram (ECG) and measurement of systolic time intervals (STIs) are particularly valuable methods. The ECG appears to be highly sensitive to the electrophysiologic actions of psychotropic drugs, but the correction of QT interval for changes in heart rate remains unsatisfactory. STIs are also highly sensitive indices of cardiovascular side effects but they lack specificity and are substantially influenced by peripheral vascular changes and intracardiac conduction delay. Nevertheless, STIS have value as a screening test for cardiovascular actions of drugs, and their specificity may be enhanced by combination with ECGs and measurements of blood pressure.