Aim: This study aimed to explore the role of peritoneal ultrafiltration (UF) in cardiorenal syndrome (CRS) patients for fluid and metabolic control. Background: Peritoneal UF is safely and efficiently used for the management of CRS. It has been shown to provide efficient UF in hypervolemic patients. Methods: Thirty (20 males and 10 females) CRS patients were treated by peritoneal dialysis (PD) and UF. The baseline data of the patients (demographics, causes of heart failure, the presence of pacemaker or implantable cardioverter-defibrillator, the need for extracorporeal UF or paracentesis or thoracentesis, comorbidity, drugs, left ventricular ejection fraction [LVEF] and pulmonary artery systolic pressure [PAPs], pericardial effusion, physical examination, body weight, NYHA class, dialysis regime, urine output, N-terminal pro-B-type natriuretic peptide [NT-proBNP] level, hemoglobin, estimated glomerular filtration rate [eGFR], and other routine biochemical determinations) were recorded at the onset, every 6 months, and then annually. Echocardiograms were performed at baseline and after 6 and 12 months. The time points of complications associated with PD, the need for hemodialysis, the day of death, and causes of death were documented. Results: Mean age was 69 ± 8 years (range 49–84 years). The average PD duration was 18.25 ± 14.87 months. According to the CKD-EPI, initial mean GFR was 34.34 ± 11.9 mL/min/1.73 m2 (range 16.57–59.0), and this increased to 45.48 ± 26.04, 45.10 ± 28.58, and 41.10 ± 25.68 mL/min/1.73 m2 in the third, sixth, and twelfth months, respectively. There was a significant increase in the first 3 months and a significant decrease between the third and twelfth months (respectively, p = 0.018 and p = 0.043). There was no difference in eGFR levels between baseline and the end of the first year (p = 0.217). In the first 3 months, there was a significant decline in urea levels to 79.38 ± 36.65 from 109.92 ± 42.44 mg/dL and this was maintained until the end of the first year of PD therapy (after 3 months, p = 0.002; after 1 year, p = 0.024). However, there was no significant change in creatinine levels within the first year (p = 0.312). There was a significant increase in hemoglobin level up to the end of the first year of PD (after 3 months, p = 0.000; after 12 months, p = 0.013). There was a marked decrease in NT-proBNP levels in the first 6 months (p = 0.011). Functional capacity (according to NYHA classification) improved in all patients by the third month of PD treatment (p < 0.001). This early improvement was maintained in many patients during the following 12 months (p < 0.001). There was a marked decrease in NT-proBNP levels in the first 6 months (p = 0.011). At the end of the first year, there was an approximate 15% reduction in NT-proBNP levels (p = 0.647). Hospitalizations decreased to 6 ± 15 days/patient-year (range 18–122 days) from 62 ± 24 days/patient-year (p = 0.000). Conclusion: Peritoneal UF is a treatment method that maintains renal function and electrolyte balance, improves cardiac function, and reduces hospitalizations in CRS patients. We observed that this treatment significantly increased functional capacity and quality of life and significantly reduced hospital admissions.