Pancreas with duodenum was transplanted from healthy, male rats to the artificially diseased male rats of alloxan diabetes. He- Ne laser irradiation, immune inhibitors and their combination were applied immediately after the operation to observe their effects against rejection. The results are as follows: with the treatment of He-Ne laser irradiation at a dose of 39. 72 J/cm2, the starting time of rejection to the organs was delayed, the living time of the organs was prolonged and the intensity of rejection was lightened. The above stated effects can be stronger when laser irradiation is combined with medication of azathioprin (at the dose of 8-5-3 mg/kg/day) and the effects are colse to those of cydosporin A(CsA).