The influence of various electrodeposition conditions (current density, including volume current density, and hydrodynamic conditions in different electrode systems such as the Hull cell with a rotating cylinder electrode and a cell without stirring, including a soluble anode (W) and an insoluble anode (graphite)) on the microhardness of nanocrystalline Co-W coatings, obtained from citrate and gluconate electrolytes, is investigated. It has been shown that the volume deposition current density is a governing factor which influences the measured microhardness values due to the microhardness size effect, that is, the dependences of microhardness on electrodeposition surface area for a fixed current density and electrolyte volume. The conditions, e.g., volume current densities, for maximum microhardness are determined.