EPR Studies of radiation damage in anthracene C14H10and deuterated anthracene (C14D10) powders have been made up to a dose of 7 × 108rad. Interpretation of the spectra is consistent with that resulting from the hyperfine interaction of three equivalent protons. Excessive breadth of the spectrum of the radical produced in C14D10is attributed to a high concentration of incompletely deuterated radical resulting from the presence of C14D9H.