Thirteen elderly subjects underwent a crossover study of dopamine and dobutamine at 5 micrograms/kg/min in order to compare the systemic and regional hemodynamic effects of the two drugs, using Doppler techniques. Although both drugs decreased mean arterial pressure significantly, cardiac index and total peripheral resistance remained unchanged. Both drugs increased heart rate significantly. Since neither drug altered the common carotid, celiac or superior mesenteric flow, there was no significant change in the resistances of these flows. Terminal aortic flow increased significantly and its resistance decreased significantly with both drugs. Both dopamine and dobutamine at 5 micrograms/kg/min act as a positive inotrope in general. Out data suggest, however, that both drugs may act mainly as a positive chronotrope in the aged and that both drugs may have direct effects on the terminal aortic vascular bed since terminal aortic flow increased significantly without augmentation in the cardiac index.