The immunoregulatory effects of some anti-cancer drugs have important role in their anti-tumor mechanisms. Our results showed that doxorubicin (DXR) of 0.04 mg ?L-1 could enhance the interleukin 2 (IL-2) release and induction of lymphokine-activated killer (LAK) activity of human fetal thymocytes(HFT). Higher concentration of this drug (4 mg ?L-1) exhibited inhibition on IL-2 release but no effect on LAK activity. These data suggest that lower concentration of DXR have some immunopotentiation effects on HFT.