Aim: The purpose of the present study was to investigate the effects of various short-term cooling durations on the performance of both superelastic and thermally treated nickel titanium (NiTi) files, tested in a dynamic cyclic fatigue model. Methodology: Superelastic RaCe (FKG, La Chaux-de-Fonds, Switzerland) and thermally treated RaCe EVO (FKG, La Chaux-de-Fonds, Switzerland) files of the same size and taper (25, 0.06) (n = 45 each) were tested using a dynamic cyclic fatigue model, where the number of cycles to failure (Nf) was measured at simulated body temperature. In each group, the samples were tested as received, after 5 seconds of cooling treatment, and after 15 seconds of cooling treatment (n = 15 each). Fractured file surfaces were investigated via scanning electron microscopy. Statistical analysis was performed using a one-way ANOVA with Scheffe’s post hoc test at a significance level of 0.05. Results: Significant differences in the Nf between the tested groups were found (p 0.05) at each testing condition, where RaCe Evo files showed overall improved cyclic fatigue resistance. Only the RaCe groups at 5 second cooling showed significantly higher Nf than the control subgroup (p 0.05). RaCe EVO group, showed no significant difference between the 3 subgroups (p > 0.05). Scanning Electron Microscope (SEM) images revealed typical features of cyclic fatigue behavior in both groups. Conclusions: Short-term cooling application for 5 seconds on superelastic NiTi files showed an enhanced cyclic fatigue resistance.