Abstract Funding Acknowledgements None Introduction Conventionally, catheter movement and placement during catheter ablation (CA) is guided by X-ray fluoroscopy. In recent years, an ‘as low as reasonably possible’ principle was established to minimize the ionizing radiation dose received by the patient and the operator. Zero-fluoroscopy approach is at the extreme end of the spectrum of this principle. With exclusion of X-ray fluoroscopy, three-dimensional electroanatomical mapping system and intracardiac echocardiography are used for catheter guidance during ablation procedures. Purpose The aim of our study was to assess and compare procedural parameters and clinical outcomes of conventional X-ray fluoroscopy guided and zero-fluoroscopy CA for treatment of supraventricular tachycardias. Methods Retrospective analysis included CA procedure between April 2014 and May 2019. Five hundred and thirteen (513) patients were selected for analysis; they had confirmed diagnosis of atrioventricular nodal reentry tachycardia (AVNRT) or atrioventricular reentry tachycardia (AVRT). Patients were divided into two groups based on the use of fluoroscopy (conventional approach group - CG; zero-fluoroscopy group - ZF). Procedural data and clinical outcomes were analyzed. Two groups were compared using chi-squared test or Mann-Whithney U test when appropriate. Results There were 249 patients (44.2% males) in CG group, and 260 patients (47.5% males) in ZF group. ZF group included 113 (43.5%) pediatric patients. The groups differed in mean age (53.4 ± 16.4 years vs 30.0 ± 19.8 years (CG vs ZF), p < 0.001), postprocedural use of antiarrhythmic agents or beta blockers (55.3% vs 17.0% (CG vs ZF), p < 0.001) and type of arrhythmia (72.3% vs 60.6% AVNRT (CG vs ZF), p = 0.003). In CG group, all procedures were performed using radiofrequency (RF) energy, whereas in ZF group, cryoablation was used in 18.3% of procedures at the discretion of the operator. Mean procedural duration was longer in CG group (100.1 ± 48.8 vs 90.4 ± 83.0 minutes, p < 0.001). The mean fluroscopy time was 13.6 ± 9.3 minutes and mean dose area product was 554.1 ± 713.6 mGycm2 in the CG group. Acute success rate was higher in CG group (95.7 vs 90.7%, p = 0.027). However, the arrhythmia-free survival rate after 13.8 ± 11.0 months of follow-up was lower in the CG group (90.9 vs 96.5%, p = 0.009). Mean number of procedures per patient was 1.04 in the CG group and 1.14 in the ZF group (p < 0.001). There were no severe complications. Conclusions Zero-fluoroscopy CA of supraventricular tachycardias is associated with lower procedural success rate, but higher long-term arrhythmia-free survival rate when compared to conventional fluoroscopy guided procedures. It is possible, that these differences are stemming from somewhat different patient populations in both groups.