The effect of thermally induced birefringence in a Nd:YAG rod geometry resonator, which is simultaneously compensated by both an intra-cavity 90° rotator and an intra-cavity quarter-wave plate, is experimentally investigated. The experimental investigation shows that, compared to the resonator with thermally induced birefringence solo compensated by an intra-cavity 90° rotator or an intra-cavity quarter-wave plate, the output power from the resonator simultaneously compensated by both an intra-cavity 90° rotator and an intra-cavity quarter-wave plate increases more than 16%, and the depolarization loss decreases more than 67%. Compared to any compensation, the depolarization loss decreases about 85%.