The electrolytic deposition of NiP coatings on a rotating-disc electrode and in a high flow jet cell laboratory apparatus has been investigated. From the current density profile along the cathode, the dependences of the phosphorus content and the coating thickness on the local current density were established for different bath compositions. With increasing local current density a steep transition from high to low phosphorus content in the NiP coatings produced was observed in each plating bath. This transition can be electrochemically monitored in the jet cell by polarization measurements. The structural characterization of the coatings revealed at 12 wt.% P a change of the as-plated structure from amorphous to crystalline. The weight per cent of P at which this transition in structure occurs was found to be independent of both bath composition and type of plating cell used.