<b><i>Background:</i></b> Balloon pulmonary angioplasty (BPA) is a novel treatment option for inoperable or persistent chronic thromboembolic pulmonary hypertension (CTEPH). Little is known about renal function in CTEPH patients undergoing BPA. <b><i>Objectives:</i></b> The aim of this study was to assess the frequency of contrast-induced acute kidney injury (CI-AKI) in patients with CTEPH undergoing BPA and to evaluate the relationship between hemodynamic and renal function. <b><i>Methods:</i></b> A total of 41 CTEPH patients were included and 250 consecutive BPA sessions were analyzed for frequency of CI-AKI. The serum creatinine (SC) concentration was measured and the glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease equation before and 72 h after each BPA procedure. CI-AKI was defined as an increase of 25% or 0.5 mg/dL in SC from the baseline value within 48–72 h of contrast administration. SC and GFR were assessed before and after 3–6 months of completing the BPA treatment and correlated with hemodynamic parameters. <b><i>Results:</i></b> The SC concentration and GFR did not change significantly within 72 h after BPA (+1%, <i>p</i> = 0.921, and +4%, <i>p</i> = 0.112, respectively). CI-AKI was noted in 2 cases (0.8%). Significant improvement was noted in GFR (75.4 ± 21.2 vs. 80.9 ± 22.4 mL/min/1.73 m²; <i>p</i> = 0.012) in addition to improvement in right atrial pressure (RAP; 9.1 ± 4.1 to 5.0 ± 2.2 mm Hg; <i>p</i> &#x3c; 0.001), mean pulmonary artery pressure (49.1 ± 10.7 to 29.8 ± 8.3 mm Hg; <i>p</i> &#x3c; 0.001), cardiac index (CI; 2.42 ± 0.6 to 2.70 ± 0.6 L/min/m²; <i>p</i> = 0.004), and pulmonary vascular resistance (9.42 ± 3.6 to 4.4 ± 2.3 Wood units; <i>p</i> &#x3c; 0.001). In a subpopulation of 12 patients with impaired renal function at baseline, the relative increase in GFR was significantly correlated with relative improvement in CI (<i>r</i> = 0.060; <i>p</i> = 0.037), RAP (<i>r</i> = –0.587; <i>p</i> = 0.044), and mixed venous saturation (<i>r</i> = 0.069; <i>p</i> = 0.012). <b><i>Conclusions:</i></b> Hemodynamically effective BPA procedures improve renal function in patients with CTEPH with a minimal risk of CI-AKI in the course of treatment.