Clinical versus hemodynamic assessment of cardiac disability was compared in 187 patients with either coronary artery or valvular disease classified using the New York Heart Association classification (excluding class IV). The following variables were analyzed during rest and exercise: arteriovenous oxygen content difference (CavO<sub>2</sub>), cardiac index (CI), pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), pulmonary arteriolar resistance index (PARI) and heart rate (HR). 180 comparisons of variables were made. Hemodynamic evaluation paralleled clinical evaluation only 19 times during rest and 12 during exercise. There were 5 instances of clinical and hemodynamic distinction between class I and II, 14 between class I and III and 12 between class II and III. Correlation was best in mitral stenosis. The most useful variable was CI followed by PAP and CavO<sub>2</sub>. HR was not helpful. This study emphasizes that subjective clinical disability may not correlate with physiologic derangement in certain patients.