Introduction: Catheter ablation is superior to drugs regarding atrial fibrillation (AF) recurrence, symptoms improvement, and mortality reduction in heart failure. POLARx™ is a novel cryoballoon, with technical improvements seeking to improve outcomes. So far, its clinical evidence is restricted to a case report. Methods: To compare the POLARx™ cryoballoon procedural safety and efficacy to the already established Arctic Front Advance PRO™ (AFAP) in a single-center cohort study, consecutive patients undergoing AF cryoablation with the POLARx™ were enrolled. Data were prospectively gathered. POLARx™ patients were compared to a historical cohort of patients submitted to AF cryoablation with the AFAP. Results: Seventy patients were analyzed, 20 in POLARx™, and 50 in the AFAP group. They all underwent first-time pulmonary vein isolation, 77% were male, 94% had paroxysmal AF, median age was 62.5 years, median CHA2DS2-VASc 1, left-atrium size 34ml/m², and 65% were receiving anticoagulation. The primary end-point, all pulmonary veins isolation, was 100% in both groups. The complication rate was similar (0% POLARx™ vs. 5.7% AFAP, p=0.39). The median total procedural time was longer in the POLARx™ group (90min vs. 60min, p<0.001), but the overall time-to-isolation (TTI) (44.8sec vs. 39sec, p=0.253) and ablation time (15min vs. 13.7min, p=0.122) was similar between POLARx™ and AFAP groups, respectively. Despite equal TTI, the POLARx™ had a lower minimal temperature reached (-57ºC vs -47ºC, p<0.001). Conclusion: The novel POLARx™ cryoballoon had similar efficacy and safety compared to the AFAP. It was also associated with longer procedural times, similar TTI, and lower minimum temperature reached.