A thermoplastic molding composition comprising polycarbonate, an impact modifier, a phosphorus-containing flameproofing agent, and high purity talc is disclosed. The composition offers flame resistance for molded parts having small wall thickness, improved rigidity and resistance to stress cracking. The talc has MgO content of 30.5 to 32 wt. %, SiO2 content of 60 to 62.5 wt. % and Al2O3 content lower than 0.7 wt. % and d50 value less than or equal to 2.5 &mgr;m.