Abstract: 1-Methylhydantoin was synthesized from the reaction of methylamine, sodium monochloroacetate and sodium cyanate by “one pot” method with a total yield of 62.9%. 1Methylhydantoin was characterized by means of single crystal Xray diffraction. It crystallized in the monoclinic space group P2₁ with crystallgraphic parameters: a=0.558 9(3) nm, b=1.217 6(6) nm, c=0.809 0(4) nm；β=105.330(7)°；V=0.531 0(5) nm³；Z=4, D_c=1.427 mg/m³, μ=0.116 mm^-1, F(000)=240.

Key words: synthesis, 1-Methylhydantoin, crystal structure