Conducting silver paste was prepared by using Ag nanoparticles which were synthesized by e-beam irradiation method (from KAERI); its conductivity was comparatively determined with Ag nanoparticles which were prepared by thermolysis method (commercial). The silver nanoparticles with the diameter of approximately 150nm size prepared by e-beam irradiation were mixed with glass frit and sintered for 1h at 500°C. It is presumably concluded that the wt% of silver nanoparticle, size distribution and homogenous dispersibility of Ag nanoparticles in the pastes are the critical factors for the high conductivity of the paste. Among the various wt% of silver nanoparticle in the conducting silver pastes, silver paste with 90wt% of silver nanoparticle has the highest conductivity as 1.6×10 4 Scm −1 . This conductivity value is 1.6 times higher than the Ag pastes which were prepared with silver nanoparticles obtained by thermolysis method.