Abstract: Since the discovery of antitumor activity of Sb-57 and Sb-71, about 50 analogs of them have then been tested in mice bearing Ehrlich ascites carcinoma or sarcoma 180. The main results were as follows: 1. The antimonial chelates of five complexones exhibited marked inhibiting action on Ehrlich ascites carcinoma in mice. They were the salts of EDTA-Sb (table 6-Ⅰ) and PDTA-Sb (Ⅳ), N-substituted analogs of EDTA-Sb (Ⅱ), ATA-Sb (Va) and antimonial derivatives of its analogs (Ⅶ), and CDTA-Sb (Ⅸf). Among these compounds the propylamine salt and morpholine salt were more potent than the others (such as sodium salt). 2. Ten kinds of metal complex (Hg, Bi, Pb, Zn, Mn, Cu, Co, Ni, Sn and Ba) of ATA and EDTA (Ⅲ, Ⅴ and Ⅷ) were prepared and examined for their activities, but none of them showed any inhibitory action on experimental tumors. The chelating agents (EDTA, PDTA and ATA etc.) alone also had no therapeutic effect on Ehrlich ascites carcinoma or sarcoma 180 in mice. 3. EDTA-SbNa, PDTA-SbNa (Sb-57) and ATA-Sb (Sb-71) produced a slight inhibition on the growth of sarcoma 180. The chemical feature and pharmacologic effect of antimonial chelates of EDTA and ATA are also discussed in this paper.