One of the possible reasons for low conductivity of in-situ produced dispersion strengthened copper matrix composites may be the incompleteness of the reaction between the initial reactants that remain in a state of solid solutions in the copper matrix. We report in-situ synthesis of TiB2-Cu composites starting from the powder mixtures with the limited content of copper ensuring a high probability of contact between the particles of titanium and boron and, as a result, their full conversion into the TiB2 phase. The nanoparticles were formed in a self-propagating mode in the ball milled Ti-B-Cu powder mixture corresponding to 57 vol.% TiB2-Cu composition. Afterwards, the system was "diluted" with the required amount of the copper matrix using subsequent ball milling. Highly conductive 4.5 vol.% TiB2-Cu composites showing 82-87% IACS (International Annealed Copper Standard) conductivity were obtained by Spark Plasma Sintering (SPS) of the powders.