Abstract: A liquid colorant for ABS resins is described, comprising 100 parts by weight of a pigment or dye and 25 to 2,000 parts by weight of a liquid polyester, and having a viscosity of 1,500 poises or less at room temperature. This liquid polyester is prepared mainly from an aliphatic dicarboxylic acid and a dihydric alcohol, and usually has a viscosity of 10 to 1,500 poises at room temperture. The liquid colorant has advantages such as (1) the dispersibility of the pigment is good, (2) the colorant can be weighed precisely, (3) the colorant does not deteriorate the appearence of the molded article, and (4) the colorant does not deteriorate the physical properties of the molded article.