Methylsilylphosphine, MePH(SiH3), and methyldisilylphosphine, MeP(SiH3)2, have been prepared by reaction of silylphosphinopotassium and disilylphosphinopotassium with methyl bromide. Methylsilylphosphine and dimethylsilylphosphine, Me2PSiH3, have been prepared by reaction of silyl bromide with LiAlH(PHMe)3 and LiAlH2(PMe2)2, respectively: i.r. and n.m.r. spectra of the new compounds are reported. The reactions of silyl bromide with methyl- and dimethyl-phosphine and with their potassium salts are also described.