The polymerization of acrylamide (AAM) onto calcium carbonate (CaCO3) particle surfaces induced by ultraviolet light and the properties of polyamide-6 (PA6) filled with the surface-treated CaCO3 were studied. Electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), particle size distribution, impact strength and degree of polymerization measurements were determined. After AAM polymerization, a PAAM layer was formed on the CaCO3 surface. This layer tightly banded the CaCO3 particle and could not be washed away by acetone. A N-1s peak was observed in the ESCA spectra of the treated CaCO3 particles. The average particle size of the treated CaCO3 increased compared to that of the original CaCO3. The interfacial interaction and impact strength of the treated CaCO3-filled PA6 were enhanced compared to those of the untreated CaCO3-filled PA6. (C) 2004 Society of Plastics Engineers.