Laser immunotherapy (LIT) uses laser irradiation and immunological stimulation to treat metastatic cancers. The current mode of operation of LIT is through dye-enhanced non-invasive irradiation. Although this treatment has given promising results, there are still a number of challenges with this method, such as limited light penetration for deep tumors and strong light absorption by highly pigmented skins. Interstitial laser immunotherapy (ILIT), using a cylindrical diffuser, is designed to overcome these limitations. In this study, rat tumors were treated by ILIT with an 805 nm laser and varying doses of glycated chitosan, an immunological stimulant. The goal was to observe the effects of differing doses of the stimulant on the survival of the tumor-bearing rats. The results suggested that the optimal dose of glycated chitosan is in the range of 0.1 to 0.3 ml per rat tumor.