Silver/nanodiamond (ND) composites with varying amounts of NDs were produced from powders via ball milling and subsequent consolidation and deformation by high-pressure torsion (HPT). The ball milling parameters, i.e. milling time and milling speed, were increased together with increasing ND content to enable a good ND distribution in the Ag powder and to dissolve the ND agglomerates. To study the influence of oxygen contamination, both the milling and consolidation of the powders were also done in an inert Argon atmosphere. An increase of the ND content from 0.1 to 5.0 weight percent resulted in hardness values of up to 175 HV compared to 105 HV of pure Ag powder. A homogenous microstructure for all ND contents was achieved after ball milling for 6 hours at 300 rpm and after at least 30 HPT revolutions at a hydrostatic pressure of 5 GPa at room temperature. Agglomerates in the Ag matrix were investigated with energy dispersive X-ray spectroscopy (EDX) to detect possible contaminations from the milling process and their influence on the saturation hardness and microstructure.