A flame retardant composition comprises the following components: (a) a polymer latex comprising (i) a bis(hydrocarbyl)vinyl phosphonate, preferably bis( Beta chloroethyl)vinyl phosphonate, (ii) a vinyl halide or vinylidene halide such as vinyl chloride or vinylidene chloride, (iii) an alkyl acrylate and optionally, (iv) another derivative of acrylic acid or methacrylic acid; (b) a phosphorus source selected from (i) a co-condensate of bis( Beta -chloroethyl)vinyl phosphonate and dimethyl methyl phosphonate or a condensate of bis( Beta chloroethyl) vinyl phosphonate, (ii) tetrakis (hydroxymethyl) phosphonium halide or hydroxide, (iii) N-hydroxymethyl-3(dimethylphosphoro) propionamide, (iv) tris(2,3-dibromopropyl phosphate), (v) water-insoluble ammonium polyphosphate and (vi) water-insoluble ammonium salt of metaphosphoroamidic acid; (c) urea; (d) an aminoplast selected from a melamine formaldehyde or urea formaldehyde; and (e) optionally, a phosphate plasticizer. These compositions are useful as binders, saturants, impregnants and coatings for flammable materials.