PURPOSE: To obtain a thermoplastic molding composition having a high m.p., a high glass transition temp., high thermal formation stability and a high crystal degree by adding prescribed amts. of a filler, a rubber elasticity copolymer or the like, to a partially arom. copolyamide having a specified compsn.

CONSTITUTION: A partially arom. copolyamide comprising 50-90 wt.% units derived from terephthalic acid and hexamethylenediamine, 5-30 wt.% units derived from -caprolactam and 5-30 wt.% units derived from isophthalic acid and hexamethylenediamine is prepd. and 60-100 wt.% of the partially arom. copolyamide is mixed with 0-40 wt.% fibrous or particulate filler such as calcium silicate, 0-40 wt.% rubber elasticity copolymer such as ethylene- propylene-diene rubber and 0-30 wt.% ordinary additives and processing aids to produce the objective thermoplastic molding composition.