Abstract : The development of chronic kidney disease (CKD) is one of the most common conditions comorbid with chronic obstructive pulmonary disease (COPD). The aim of the study was assessment of renal blood flow in patients with COPD with and without CKD. 142 patients with COPD of 2-4 degrees were examined. The assessment of renal blood flow was carried out using the ultrasound by color Doppler mapping. All examined patients were divided into 2 study groups: Group I consisted of 71 patients with COPD with eGFR > 60 ml / min / 1.73m2, group II consisted of 71 patients with COPD with eGFR ≤60ml/min/1.73m2. The progression of kidney dysfunction in patients with COPD was accompanied by a significant decrease in exercise tolerance, worsening of the clinical condition of patients according to the clinical assessment scale and COPD assessment test with a decrease in the functional activity of patients. In COPD patients with CKD, changes were also noted at the level of the lobar and segmental renal arteries, characterized by a significant increase in pulsatile and resistance indices as well as there was a decrease in speed indicators during diastole, systole, and the average blood flow velocity. The COPD patients with renal dysfunction had changes noted at the level of the lobar and segmental renal arteries, characterized by a significant increase in pulsatility and resistance indices. Moreover, there was a decrease in speed indicators during diastole, systole, and the average blood flow velocity.