Radiofrequency (RF) catheter ablation is widely accepted as a first-line therapy for cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). The novel DiamondTemp (DT) catheter with temperature feedback during RF ablation has been released recently on the market. The purpose of this study was to evaluate the impact of DiamondTemp (DT) technology on ablation efficiency during AFL. In this single-center study, 30 consecutive patients with typical AFL indicated to ablation of CTI were included. The first 15 patients underwent CTI ablation using 8-mm tip catheter, and the following 15 patients underwent temperature-controlled RF ablation using DT catheter. The endpoints were number and mean total duration of RF applications, mean temperature reached in the setting of CTI, procedural times, and fluoroscopy times. There were no significant differences between the two groups concerning baseline characteristics. Mean duration of the each application (71.5s ± 30.6 vs 12.4s ± 13.2, p value < 0.001), mean total duration of RF applications (517,73s ± 377,96 vs 112,8s ± 43,58; p value < 0.001), procedural times (51.6min ± 24.2 vs 38.6 ± 8.2; p = 0.03), and fluoroscopy times (16.2min ± 10.2 vs 8min ± 4.24; p = 0.005) were longer in the 8-mm ablation catheter group. Mean temperature measurements (51.9°C ± 3.59 vs 56.7°C ± 3.34, p value < 0.003) were as well lower in the 8-mm ablation catheter group. Catheter ablation of CTI-dependent AFL by means of DT resulted in a significant reduction of total and single application RF delivery time, procedure, and fluoroscopy times.