Plain chest x-rays, twelve-lead electrocardiograms, and M-mode echocardiograms were analyzed in 50 control patients and 79 consecutive patients with pulmonary hypertension documented at cardiac catheterization in order to determine the relative values of these noninvasive techniques as screening tests in detecting pulmonary hypertension. The sensitivity and specificity of selected findings previously described as being associated with pulmonary hypertension were calculated for each test. All test results were found to have sensitivities too low to function as satisfactory noninvasive screening techniques. Most findings were highly specific for pulmonary hypertension when present. Patients with pulmonary vascular disease were detected more frequently than those with pulmonary hypertension due to pulmonary venous congestion.