A series of 2-N and 2-O-substituted 2-oxo-4-chloromethyl-1,3,2-dioxaphosphorinaiies were prepared by reaction of amines and alcohols with 2-oxo-2-chloro-4-chloromethyl- 1,3,2-dioxaphosphorinane. The structure of compounds obtained was proved by means of H-1 and C-13 NMR spectroscopy. Some cyclic amidocyclophosphates possessed biological activity as inhibitors of mitotic fission and of Na+/H+ exchange.