The aim of this study was to evaluate the protective effect of low molecular weight ${eta}$-glucan (LMG) against doxorubicin (DOX)-induced immune suppression of tumor-bearing mice. The tumor size and spleen cell functions such as spleen cell proliferation, cytokine production (interferon-${gamma}$ and interleukin-2), and the population of $CD4^+$ and $CD8^+$ T cells were estimated. In the tumorbearing mice, the tumor size was significantly (p<0.05) decreased by DOX treatment. However, there was no significant difference between mice treated with high molecular weight ${eta}$-glucan (HMG) and mice treated with LMG. Spleen cell proliferation and cytokine production were significantly (p<0.05) decreased in only DOX treated group, but increased in all ${eta}$-glucan treated groups with DOX. Moreover, the populations of $CD4^+$ and $CD8^+$ T cells were also increased in the LMG-treated group. It appears that LMG effectively reduces the DOX-induced immune toxicity through activation of immune cells such as splenocytes.