AIM A person with a drop of more than 10% in nocturnal arterial blood pressure during the circadian rhythm is referred to as a dipper and one with a smaller decrease is referred to as a non-dipper. In our study, we aimed to compare the thrombolysis in myocardial infarction (TIMI) frame count in non-dipper and dipper hypertensive patient groups who had normal coronary artery angiography. METHODS Patients with normal coronary arteries and with ambulatory blood pressure monitoring follow ups were retrospectively investigated and 60 patients (35%, female) were included in our study. The patients were grouped as dipper (n = 30) and non-dipper (n = 30) hypertensives. RESULTS The TIMI frame counts in all three coronary arteries and the mean TIMI frame count in the dipper hypertensive patient group were significantly lower than those of the non-dipper hypertensives (right coronary artery TIMI frame count: 16.83 ± 3.70; 21.63 ± 3.44, p < 0.001; circumflex artery TIMI frame count: 21.28 ± 3.52; 25.65 ± 3.61, p < 0.001; left anterior descending artery TIMI frame count: 34.20 ± 2.80; 37.05 ± 3.30, p = 0.001; corrected left anterior descending artery TIMI frame count: 20.05 ± 1.63; 21.74 ± 1.95, p = 0.001; mean TIMI frame count: 19.31 ± 2.3; 22.94 ± 2.61, p < 0.001). The body mass index (BMI) was 23.79 ± 2.81 kg/m2 in the dipper patient group, while it was 25.47 ± 2.92 in the non-dippers. BMI was found to be significantly higher in the non-dipper group than in the dipper group (p = 0.027). CONCLUSION In this study, TIMI frame count, which is a simple, productive, objective and reproducible method for determination of microvascular changes, was found to be higher in non-dipper hypertensive patients than in the dipper patients.