The second paper in a set of reviews of radiation effects on thermal properties of polymers is devoted to polytetrafluoroethylene (PTFE). The specificity of the radiation physics and chemistry of this material is relatively well investigated and it is widely used in different applications under radiation impact. Degradation of thermal and structure properties is discussed, and models for the description of these effects are presented. Specific problems such as the action of different kinds of radiation, dose rate effects, especially under vacuum, and deviation of PTFE structure from the two-phase model are also examined.