Background: Atrioventricular reentrant tachycardia (AVRT) is the most common tachycardia, accounting for 70% of regular narrow-QRS arrhythmias in children. Because of the potential disadvantages of a life-long drug therapy and relatively favourable results from radiofrequency catheter ablation (RFCA) therapy in adults, the indications for ablation therapy in children with preexcitation syndrome (PS) need to be considered. Aim: To assess efficacy and safety of RFCA in children and adolescents with PS. Methods: The study population consisted of 302 consecutive, symptomatic, drug-refractory patients with PS undergoing RFCA. Two age groups were selected: 52 patients younger than 19 years (24 females, age 15.38±2.53 years); and 250 adults (115 females, age 38.67±13.1 years). In all study patients electrophysiological study and radiofrequency catheter ablation were performed. Comparative analysis between groups was performed with respect to procedure duration, fluoroscopy exposure time, location of accessory pathways (AP), success rate, recurrences and complications. Results: No significant differences between the groups were noted with respect to procedure duration and exposure time. Success and recurrence rates did not differ between the two-age groups. The mean procedure time for children was 124.12±43.48 min (range 45-285) and for adults – 126.3±61.49 min (range 25-330) (NS). The mean fluoroscopy time for children was 27.95±16.86 min (range 4-75) and for adults – 31.27±25.51 min (range 1-131) (NS). The initial RF ablation procedure was successful in 48 (92.31%) children and in 233 (93.2%) adults (NS). Recurrence rate was 12.5% (6 patients) in children vs. 8.58% (20 patients) in adults (NS). In one child (1.92%) and in two adult patients (0.8%) serious complication occurred (NS). Electrophysiological study revealed significantly more frequent presence of the right free wall and right antero-septal AP in children than in adults (21.15 vs. 7.6%, and 17.31 vs. 5.2%, respectively, p <0.01). In adults more frequent left antero-lateral AP was detected: 32.4 vs. 7.69%, p <0.01. Conclusions: Radiofrequency catheter ablation is a safe and efficient procedure in paediatric patients with preexcitation syndrome. Effectiveness, safety, recurrence rate and RFCA procedural aspects, including total procedure time and fluoroscopy time, are comparable in paediatric patients with PS and in adults.