This paper presents an experimental setup and experimental data for critical heat flux at high reduced pressures. Studies on critical heat flux during the forced flow of Freon R125 in a vertical channel with a diameter of 0.95 mm and length of 100 mm were performed. The hydraulic loop of the setup provides stable flow conditions at the inlet of the test section under pressures up to 2.5 MPa and temperatures up to 200 °C. The measured parameters were the mass flow rate, pressure and temperature at the inlet and outlet of the test section, the joule heating power and the wall temperature in the six cross-sections along the tube. An automated data-acquisition system was used during the experiments. A comparison between the experimental and calculated data is presented.