Introduction: This study evaluated the cyclic fatigue resistance (CFR) of Reciproc (R25 and R40; VDW, Munich, Germany) and Reciproc Blue (R25 and R40, VDW) instruments used in an artificial S-shaped canal. Methods: A total of 80 files were tested in an S-shaped canal (n = 20 for each file, Reciproc R25 and R40 and Reciproc Blue R25 and R40). This study compared Reciproc R25 with Reciproc Blue R25 files and Reciproc R40 with Reciproc Blue R40 files. All files were rotated in an S-shaped artificial canal until fracture. CFR was determined by recording the time to fracture in the artificial canal. The length of each fractured fragment was measured in millimeters. An independent sample t test was used to analyze the data. Results: Between the R25 files, Reciproc Blue instruments showed significantly greater CFR than the Reciproc files in the apical and coronal curves (P <.05). Between the R40 files, Reciproc Blue instruments exhibited greater CFR in the apical and coronal curves (P <.05). There was no difference in the fractured fragment lengths of the Reciproc Blue files compared with the Reciproc files (P >.05). Conclusions: The Reciproc Blue R25 and R40 files showed greater CFR than the Reciproc R25 and R40 files in an S-shaped canal.