Slow coronary flow (SCF) in a normal-appearing coronary angiogram is a well-recognized clinical entity, but its etiopathogenesis remains unclear. The aim of the study was to evaluate echocardiographic features in patients with SCF. Thirty-four patients with angiographically proven SCF (group I) and 25 patients with normal coronary flow (group II) were enrolled in the study. The diagnosis of SCF was made with use of the "TIMI frame count (TFC)'' method. All patients underwent complete transthoracic echocardiographic examination (M-mode, 2-dimensional [2-D], and Doppler parameters such as color, continuous, pulsed wave). There were no significant differences with respect to systolic parameters between the 2 groups; in spite of these, group I showed impaired left ventricular diastolic patterns compared to group II. Group I patients had higher peak late diastolic filling velocities due to enhanced atrial systole (A), lower peak (E/A) diastolic filling velocity ratios, and longer isovolumetric relaxation times compared with group II, and these were statistically significant (p<0.001). In conclusion; the authors detected diastolic filling abnormalities and showed diastolic dysfunction in patients with SCF.