Coronary neovascularity may be formed in patients with the left atrial thrombus, and coronary artery disease may be associated with valvular heart disease. From August 1989 through September 1990, 109 patients over 40 years old with valvular heart disease were performed coronary arteriogram to evaluate the incidence of the associated coronary artery disease. And 9 patients with left atrial thrombi detected noninvasively were also performed coronary arteriogram to evaluate the significance of the neovascularity to predict the left atrial thrombus. The results were as follows : 1) Significant coronary arterial lesion(greater than 50% narrowing of the luminal diameter) was noted in three of 109 patients over 40 years old(2.8%), but there was no typical chest pain in all of the three patients. 2) The coronary neovascularity was found in 19 of 118 patients -18 with mitral valvular disease and one with combined valvular disease. All of the patients with the coronary neovascularity had established atrial fibrillataion and the neovasculaity was originated from the left circumflex artery in all of them. 3) Prosthetic valve replacement was performed in 42 of 118 patients during the study period and left atrial thrombus was found in ten patients with mitral valve disease. Neovascularity on coronary arteriogram was detected in six patients(sensitivity 60%) of the above 10 patiets, and 28 patients without neovascularity had no left atrial thrombus (28/32, specificity 87.5%). Our observation revealed that neovascularity might represent the left atrial thrombus in valvular heart disease, and the incidence of the associated coronary artery disease in valvular heart disease was very low(2.8%) in Korea. Coronary arteriography as a routine preoperative evaluation might be unnecessary in valvular heart disease in Korea.