The invention relates to the cosmetic use of polysaccharide compounds containing non-polymer siloxane graft(s) that may be obtained by reacting a polysaccharide and a siloxane compound corresponding to formula (I), especially for the cosmetic treatment of keratin materials. The invention also relates to compositions comprising the said polysaccharide compounds in a cosmetically acceptable medium, and also to certain novel polysaccharide compounds containing non-polymer siloxane graft(s).