Nickel electrodeposits on brass substrates were prepared in vigorously stirred baths of NiCl2 1.22M and NISO4 1.22M in a wide range of current densities, 1-300 mA cm(-2), at a constant charge density 146.3 Cb cm(-2), at a constant bath temperature of 50 degrees C and at pH values 0.1 or 0.5-5. Their selective orientation and structure were studied by means of the XRD, Electron Microscopy and Optical Microscopy methods. Also, the changes in the pH of the bath solutions during electrolyses and the electrochemical efficiencies were determined. It was shown that the Cl- ions favour the successive appearance of the texture axes [110](A) and [211] while the SO42- ions favour the successive appearance of the texture axes [110](A), [110], [210] and [110](B); all the above texture axes appear in a Watt’s bath which contains both the Cl- and SO42- anions. The electrochemical efficiency strongly depends on the nature of the anion, current density, the initial pH value and the corresponding texture axes kinds. In the boundaries between two successive texture axes regions the variation of the electrochemical efficiency showed abrupt changes. The changes in the pH of the bath solution (caused by the H3+O discharge process in the NiCl2 bath and by this process together with the OH- discharge on the anode in the NiSO4 bath) depend also strongly on the above electrolysis conditions. The structure of the Ni deposits also depends on these conditions and is generally well correlated to the corresponding texture axes. Generally, the structure of the Ni deposits in the NiCl2 bath is characterized as a porous, spongy, dendritic, pyramidic structure while that in the NiSO4 bath as a non porous and pyramidic spheroidised structure. A general mechanism for the Ni electrodeposition was discussed which correlates well the involved intermediates (which are different in the two baths) and the observed texture axes and also explains the variation of the electrochemical efficiency with current density and pH and the changes in the pH of the bath solutions.