Background: Cooling the dialysate is an important factor that contributes to the hemodynamic stability in patients during hemodialysis. The aim of this study was to determine the effect of cool dialysate on VITAL SIGNS, and the adequacy and common complications of hemodialysis. Materials and Methods: The present crossover, triple-blind, clinical trial was performed on 62 dialysis patients, who were selected through stratified block randomization. First, one group underwent hemodialysis using a cool dialysate (35° C), and the other received routine hemodialysis (36. 5° C). Each patient received a total of eight hemodialysis sessions. Then, treatment methods were swapped, and each group received the other group's method. The patients' blood pressure, pulse rate, and temperature were measured before dialysis, and in the first, second, third, and fourth hours of dialysis. The frequency of common complications of hemodialysis and dialysis efficacy were measured. The marginal model and Generalized Estimating Equations (GEE) were used to analyze the data. Results: The participants' systolic (p = 0. 01) and diastolic blood pressures significantly increased with a decrease in temperature (p = 0. 005). The patients' pulse rate (p = 0. 143), adequacy of dialysis (p = 0. 922), and common complications of hemodialysis did not significantly differ between the two temperatures (p > 0. 05). Conclusions: Reducing dialysate temperature from 36. 5 to 35° C led to hemodynamic stability; the blood pressure of the patients undergoing hemodialysis was more stable with the cool dialysate method and the number of drops in the blood pressure during the hemodialysis was reduced.