In the γ-radiolysis of aqueous solutions of indole-3-acetic acid (IAA), G(-IAA) was found to decrease with the absorbed dose in aerated and deoxygenated solutions. In the presence of OH radical scavengers, G(-IAA) was not negligible indicating thereby that OH radicals alone are not responsible for IAA decomposition as had been postulated earlier. Radiolytic products of IAA are mainly indole derivatives with some of their properties similar to those of IAA. The uv spectra of irradiated IAA solutions showed a very interesting behaviour in that three isobestic points were observed and absorption at 245 nm showed an increase with increasing dose. RFvalues, colour reactions and spectral characteristics of some of the products are presented.