The measurement of the thrombosis in myocardial infarction (TIMI) frame count is a simple method for evaluating coronary blood flow. Although it is well known that slow coronary flow is present in patients with coronary artery ectasia (CAE), the effects of coexisting stenosis and the severity of ectatic involvement on coronory flow have not been adequately studied. Thus, we examined (1) the effect of coexistence of obstructive coronary artery disease on TIMI frame count (TFC) and (2) the relation between the severity of ectatic involvement and TFC in patients with CAE. Ninety-seven study patients with CAE were examined in two steps to determine if they were appropriate in terms of the aim of this study. In the first step, ectasias were divided into three groups: an isolated CAE group, a CAE group with coexisting nonsignificant stenosis, and CAE with coexisting significant stenosis. In the second step, ectasias were subdivided into three groups: CAE with one segment, two segments, and three segments (or diffuse) involvement. The TIMI frame counts for the right coronary artery (RCA), the left circumflex coronary artery (LCx), and the left anterior descending artery (LAD) in the ectasia,roup were significantly higher than that of the control group (P < 0.001 P < 0.05, P < 0.05, respectively). The presence of coexisting nonsignificant stenosis or coexisting significant stenosis in patients with CAE did not influence TFC (P > 0.05, For all). In addition, the severity of ectasia involvement, regardless of the localization of ectatic segments and the type of the affected vessel. did not change the TFC (P > 0.05, for all). These results suggest that neither the coexisting stenosis nor the extent of involvement significantly affect TFC in patients with coronary ectasia.