Objective: The quantitative parameters which are used to assess the severity of aortic regurgitation (AR) provide the most accurate information whereas these parameters are difficult and time-consuming. The aim of this study was to get a practical parameter to use in daily practice for assessing the severity of aortic regurgitation. Methods: The study was an observational cohort study on diagnostic accuracy of severity of aortic regurgitation. Thirty-seven patients with aortic regurgitation determined by quantitative parameters (18 patients with severe aortic regurgitation and 19 patients with moderate aortic regurgitation) were included in this study. Each patient’s diastolic flow pattern in the descending aorta was examined by pulsed wave Doppler. Systolic and diastolic flow time-velocity integral (TVI), TVI time, systolic and diastolic TVI ratio in the descending aorta were evaluated. In addition to these parameters, dP/dt, peak acceleration time and end-diastolic flow velocity in the diastolic flow were determined. We investigated whether there a significant difference between two groups or not. Receiver operating characteristic (ROC) analysis was used to determine the optimal cut-off values of echocardiographic parameters which were used to identify the severity of aortic regurgitation. Results: The study population was composed of 16 female and 21 male patients. Their mean age was 46.5 years. The mean diastolic flow TVI of patients who had moderate and severe aortic regurgitation was found 10.1 cm and 18.6 cm, respectively (p<0.001). In the ROC curve analysis, the values of diastolic flow TVI above 13.5 cm was found to have 83% sensitivity and 90% specifity to predict the severity of aortic regurgitation (AUC: 0.91, 95% CI 0.80-1.0, p<0.001). Also we investigated the other parameters like systolic flow TVI, the ratio of systolic and diastolic flow TVI, mean diastolic flow time, mean systolic flow time, the ratio of systolic and diastolic flow time, end-diastolic velocity, peak acceleration time, dP/dt values in evaluation of diastolic flow in the descending aorta. These parameters were found statistically significant in assessing the severity of aortic regurgitation but their statistical power was weak. Conclusion: TVI of diastolic flow which is measured with pulsed wave Doppler in descending aorta could be a practical parameter in assessing the severity of aortic regurgitation.