Provided is a quinacridone pigment composition for coloring plastics, particularly engineering plastics. The quinacridone pigment composition has high transparency and high color strength and also has high heat resistance, so that discoloration during molding of a resin (a color change of a molded plate) is very small. Also provided are a masterbatch and a resin molded product that contain the pigment composition. The pigment composition for coloring resins contains a quinacridone pigment and a pigment that absorbs fluorescence in a wavelength range of 500 to 600 nm. The inventors have found that, when the pigment composition is used as a colorant of a resin molded product subjected to a high-temperature thermal history, the change in color, i.e., the discoloration, of the resin molded product obtained is very small. Thus, the present invention has been completed.