[(4,4-Dimethyl-2-oxo-1,3-oxazolidin-3-yl)methyl]phosphonic acid.

The title compound, C6H12NO5P, was synthesized as an intermediate phase in a search for new N-(phosphonomethyl)glycine derivatives. The molecules are held together by O-H...O hydrogen bonds, forming chains along the b axis in the crystal structure. The observed molecular structure is compared with that calculated by the density functional theory method.