A series of new prodrugs: [bis(2-chloroethylamino)phosphoryloxy]methyl acetate, [bis(2-chloroethylamino)phosphoryloxy]methyl pivalate and [bis(2-chloroethylamino)phosphoryloxy]methyl benzoate, was obtained in the reaction of isophosphoramide mustard (iPAM) with the corresponding acyloxymethyl halides. The cytotoxic activity of these new compounds is also shown. All compounds were highly active in the inhibition of cancer cell proliferation against the human lung (A594), prostate (PC-3) and breast (MCF-7) cancer cell lines.