  A bulk polycrystalline sample of YBa_(2)Cu_(3)O_(7-\delta) (\delta \approx
0.1) has been irradiated by \gamma-rays with ^{60}Co source. Non-monotonic
behavior of T_{c} with increasing irradiation dose \Phi (up to 220 MR) is
observed: T_{c} decreases at low doses (\Phi < 50 MR) from initial value
(\approx 93 K) by about 2 K and then rises, forming a minimum. At higher doses
(\Phi > 120 MR) T_{c} goes down again. The temperature width of resistive
transition increases rather sharply with dose below 75 MR and drops somewhat at
higher dose. The results observed are discussed, taking into account the
granular structure of sample studied and the influence of \gamma-rays on
intergrain Josephson coupling.
