A carboxylated polymer composition which comprises (A) 100 parts by weight of a carboxylated polymer obtained by copolymerizing (a) an alpha , beta -unsaturated carboxylic acid with (b) a compound having at least two ethylenically unsaturated groups and (B) 0.01 to 20 parts by weight of at least one of (c) a polyhydric alcohol/fatty acid ester and (d) an alkylene oxide adduct of a polyhydric alcohol/fatty acid ester. The composition has excellent solubility in water and is highly effective in thickening aqueous solutions. It is hence suitable for use as a thickener for various aqueous solutions.
