The hybrid Silver(Ag) nanoparticles were synthesized by gamma-irradiation, and characterized by field-emission transmittance electron microscopy (FE-TEM), field-emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDXS). The electron microscopy images show that well-dispersed Ag nanoparticles of about 3-7 nm were loaded to the outer and inner side of SiO2 nanoparticles of about 5-30 nm. Antifungal efficiency of the hybrid nanoparticles was tested against Aspergillus flavus ATCC 64025, Aspergillus fumigatus ATCC 16424, Aspergillus terreus ATCC 46941, Candida albicans ATCC 10231, Candida albicans A207(clinical isolate), Candida glabrata ATCC 48435, Candida krusei ATCC 6258, Candida lusitaniae ATCC 42720, Candida parapsilosis ATCC 34136, Candida tropicalis ATCC 13803, Cryptococcus neoformans ATCC 36556, and Mucor ramosissmus ATCC 90286. At the presence of hybrid Ag nanoparticles at 1 ppm, they did not grow fully even after 58 hrs except for Cryptococcus neoformans ATCC 36556. The hybrid Ag nanoparticle can be used for antifungal agents.