Networked $SnO_2$ nanowires were uniformly functionalized with Pd nanoparticles via ${gamma}$-ray radiolysis. The Networked $SnO_2$ nanowires were fabricated through a selective growth method. The sensing properties of the Pd-functionalized $SnO_2$ nanowires were analyzed in terms of their response to $NO_2$ and CO gases. The response time and sensitivity of the sensors were significantly improved for $NO_2$ at lower temperatures by the Pd functionalization. The enhancement in the sensing properties is likely to be due to the spillover effect of the Pd nanoparticles.