The effect of Al3+ on the cathodic current efficiency, deposit morphology, crystallographic orientations and polarisation behaviour of the cathode during electrodeposition of nickel from acidic sulfate solutions was investigated. Higher concentration of Al3+ (> 10 mg dm(-3)) significantly deteriorated the surface quality of the nickel deposit as well as the current efficiency. X-ray diffraction studies revealed that the ( 200) plane was the most preferred crystal plane and was not affected by the presence of varying concentration of Al3+ in the electrolytic bath. The presence of Al3+ caused polarisation of the cathode, which increased with increasing Al3+ concentration. The effect of Al3+ on the electrokinetic parameters: Tafel slope (b), transfer coefficient ( a) and exchange current density (i(0)) were also investigated.