The book systematizes and critically evaluates the published experimental data, as well as tables and equations for four methane-series freon: freon-20, 21, 22, 23. Based on the processing of the most reliable experimental results, the authors compiled equations for which detailed tables of the thermophysical properties of these substances are calculated in the temperature range from normal boiling points to 473 K and the pressure from 0.1 to 20 MPa. The vast majority of these tables are published for the first time. The book is intended for employees of research and design organizations working in the field of thermal physics, cryogenics, chemical technology, can also be used by teachers, graduate students and students of engineering-physical and chemical specialties.