For the first time, a novel carbon nanotube bed electrode impregnated with silver–nanoparticles (AgNPs) for the determination of trace amounts of gabapentin (GBP) is described. We synthesized the AgNPs via a new procedure. The voltammetric behavior of the electrode was investigated by cyclic voltammetry. There were linear relationships in the ranges from 3.1×10−9 to 2.9×10−2 M and from 1.0×10−8 to 1.0×10−2 GBP with square wave and differential pulse voltammetric peak currents, respectively. The detection limits were 5.6×10−10 and 9.7×10−9 M, respectively. The electrode showed excellent response over a period of 2 months and was successfully applied in human plasma and pharmaceutical capsular products.