A systematic investigation of the electrical characteristics of beta-Ga2O3 Schottky barrier diodes (SBDs) has been conducted under high-dose Co-60 gamma radiation, with total cumulative doses reaching up to 5 Mrad (Si). Initial exposure of the diodes to 1 Mrad resulted in a significant decrease in on-current and an increase in on-resistance compared to the pre-radiation condition, likely due to the generation of radiation-induced deep-level acceptor traps. However, upon exposure to higher gamma radiation doses of 3 and 5 Mrad, a partial recovery of the device performance occurred, attributed to a radiation annealing effect. Capacitance-voltage (C-V) measurements showed a decrease in net carrier concentration in the beta-Ga2O3 drift layer, from similar to 3.20 x 10(16) to similar to 3.05 x 10(16) cm(-3), after 5 Mrad irradiation. Temperature-dependent I-V characteristics showed that 5 Mrad irradiation leads to a reduction in both forward and reverse currents across all investigated temperatures ranging from 25 to 250 degrees C, accompanied by slight increases in on-resistance, ideality factors, and Schottky barrier heights. Additionally, a slight increase in reverse breakdown voltage was observed post-radiation. Overall, beta-Ga2O3 SBDs exhibit high resilience to gamma irradiation, with performance degradation mitigated by radiation-induced self-recovery, highlighting its potential for radiation-hardened electronic applications in extreme environment.