Purpose: The article presents the adoption of thermal imaging techniques in assessing methodology of the fatigue degradation degree of the polymeric materials. Design/methodology/approach: Epoxy composites reinforced with glass fiber have been subjected to three point method fatigue bending. The degraded materials were then tested using thermovision method. Findings: In experiments the temperature changes velocity of the samples was determined in the conditions of infrared radiation. The dependence between speed up of temperature and the number of fatigue cycles was determined. With an increasing a number of fatigue cycles drop in temperature speeds up was observed. Research limitations/implications: Restriction is a condition of loading state - as homogeneous as possible, and hence the homogeneous degradation state of the material. Practical implications: Designated diagnostic relation gives a basis for non-destructive evaluation of the degree of exhaustion of load-bearing capacity of the material. Originality/value: Original value of the paper are the experimental results proving the effectiveness of non-destructive thermographic methods for polymeric materials diagnosis.