The effect of gamma-irradiation on oxygen content and kinetic parameters of high temperature ceramic Y1Ba2Cu3O7-delta (YBCO) superconductor have been investigated. The bulk samples prepared by the standard solid-state method were irradiated by gamma-rays of different dose in the range of 5.04 x 10(3) to 4.23 x 10(7) (R) at room temperature. The effects of irradiation on surface morphology viz. grain size, porosity and the presence of some impurity phases have been studied by scanning electron microscopy (SEM). The changes in transition temperature (T-c) and the drop in T-c (T) have been discussed in terms of change in oxygen value (O-value) in unirradiated and irradiated samples due to out-diffusion of oxygen. The oxygen contents 5 for both the unirradiated and irradiated samples have been precisely determined by standard iodometric titration technique. The kinetic parameters viz. order of reaction (n) and activation energy (vertical bar Delta E vertical bar) for both the samples have been precisely estimated by thermo gravimetric analysis (TGA). The effect of gamma-irradiation on irradiated samples has been studied by Infrared (IR)-spectroscopy. (c) 2005 Elsevier B.V. All rights reserved.