Abstract: Since phosphamidases are more abundant in neoplastic tissue than normal tissue, twenty-three N-phosphorylated nitrogen mustards and ethylenephosphoramides were prepared in order to find anticancer agents with more selectivity against the malignant tumours. The compounds synthesized were listed in the Chinese text in Table 1. Preliminary pharmacological tests have revealed that the compounds (II, III, VII, VIII, and XXII) have remarkable inhibitory action against Sarcoma 180 in mice, and compound (I) possesses pronounced inhibitory activity against Yoshida Ascites sarcoma and several other animal tumours. The last one is now under clinical trials.