The properties of an electrolyte for acid bright copper deposition have been investigated. The influence of polyaniline dispersion, polysafranine dye (levelling component), poly(alkylene oxide) (wetting agent) or dialkyl disulfides (brightener) and combinations of these additives on the quality of electrodeposited coatings were studied. The presence of polyaniline dispersions increased the levelling ability by 16% and at the same time the concentration of the other additives could be considerably reduced. The electrolyte containing polyaniline dispersion could also be efficiently used under production conditions.