The modelling and optimization of Fe-Ni electroplating process from chloride-sulfate bath has been carried out via the design of experiments and response surface methodology. The developed multivariate regression models with three controllable input variables, i.e. current density) (A/dm(2)), temperature T (degrees C) and pH have been found statistically significant to predict the electroplating responses, such as platting current efficiency Y (%) and the average thickness of Fe-Ni deposited layer U (mu m). The main and interaction effects of the input variables on the process outputs have been investigated by graphical representation of response surfaces using 3D plots and 2D contour-maps. The models have been statistically validated by analysis of variance (ANOVA) that has revealed the acceptable coefficients of determination (R-Y(2) = 0.890 and R-U(2) = 0.826). The multi-response optimization of Fe-Ni electroplating process has been done using the desirability function approach. Hence, the optimal conditions of Fe-Ni electroplating process involve the following values for the design variables, J = 2.63 (A/dm(2)), T = 30 degrees C and pH = 3.61. In such conditions the quality of Fe-Ni electroplating deposit is the best according to experimental observations, giving high values for both responses Y=90.731% and U = 75.375 mu m. (C) 2015 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers.