The synthesis of Ag nanoparticles from AgNO3 in acrylamide (AM) isopropyl alcohol solution has been achieved at room temperature by using an gamma-irradiation reductive synthetic route in the field of a 2.22 x 10(15) Bq Co-60 gamma-ray source at the dose rate of 50 Gy/min for 3-6 h. The initial concentration of AM, which could be polymerized as polyacrylamide (PAM) in irradiation field, played an important role in the morphologies of the Ag particles in solution. The Ag fractals were only obtained from the Ag clusters and particles in a dilute AM solution. These faceted Ag particles aggregate to from preferentially oriented Ag crystals with dispersed fractal morphologies, which could be ascribed to diffusion-limited aggregation (DLA) model on the amorphous carbon-coated copper grid. The fractal dimension of the Ag crystallites is between 1.70 and 1.75, which is close to that in DLA model simulation (1.70). (C) 2002 Elsevier Science B.V. All rights reserved.