Abstract Glassy Carbon heat-treated to 3000°C (GC30), for which the specific heat follows from 5°K down to 0·4°K the relation C = γT + αT 3, was neutron irradiated in the Western New York reactor to different doses (20, 50, 125, 300 and 1250 hr.). In the He 4 range of temperature, the coefficient γ increases fast with the dose, with α decreasing at the same time. The combined effect results in a surprizing behavior above 2·5°K, where the specific heat decreases at first with dose and then increases after having passed through a minimum. In the lowest temperature range (below 2°K) a tail of a peak located below 0·4°K appears after irradiation with an increasing intensity. Presumably the peak is formed at about the same place as it is created in process of carbonization, the response of Glassy Carbon to irradiation being similar in this respect to the behavior of soft carbons. The relationship between the linear term γ, the height of the peak and the concentration of localized spins is discussed and problems and difficulties to be solved are indicated.