The effect of different clay dispersion methods on the mechano-dynamical and electrical properties of epoxy/clay nanocomposites was investigated. Three different clay dispersion methods (high-speed mechanical shearing, ultrasonication (US), and an optimal combination of high-speed shearing and US) were used for the dispersion of the clay in the epoxy resin. 3 wt% of an organoclay, cloisite 30B, was used as the nanoclay. Wide-angle X-ray diffraction technique and electron microscopic techniques (SEM and TEM) were used to study the morphology of the nanocomposites. Dynamic mechanical analysis was used to study the dynamo-mechanical properties. Studies on the dielectric breakdown strength (EBD) of the nanocomposites show that the EBD strongly depends on the clay dispersion time and clay dispersion method. Pulsed electro-acoustics method measurement shows that the space charge accumulation was considerably reduced in the nanocomposites. In particular, reduction in space charges after polarization depends on the dispersion of the nanofillers, the better the degree of dispersion, the lower the space charges observed.