7 Korean dogs were anesthetized with oxygen and isoflurane in different concentrations (1 vo1.%, 2 vo1.%, 3 vo1.%). Cardiovascular effects of isoflurane in different concentrations were investigated. The results were as follow: 1) Heart rate was decreased significantly (p<0.05) following increase of isoflurane concentrations. 2) Mean arterial blood pressure was decreased significantly (p<0.05) following increase of isoflur- ane concentrations. 3) Cardiac index was decreased significantly (p<0.05) following increase of isoflurane concentra- tions. 4) Left ventricular stroke work index was decreased significantly (p<0.05) following increase of isoflurane concentrations. 5) Pumonary artery pressure and pumonary artery wedge pressure were decreased significantly (p<0.05) following increase of isoflurane, but there were no significant changes in central venous pressure, systemic vascular resistance and pulmonary vascular resistance.