The invention relates to seed treatment compositions comprising active ingredient, polyarylphenol polyalkoxy ether phosphate and/or polyarylphenol polyalkoxy ether sulphate, and copolymer having polyalkoxy ether side chains. The polyarylphenol polyalkoxy ether phosphate and/or the polyarylphenol polyalkoxy ether sulphate in combination with the copolymer having polyalkoxy ether side chains are used as dispersant, especially to provide a dispersion of suspended active ingredient. The present invention also relates to methods of treating seed with such a composition.