This paper discusses the monotonicity preserving of monotone data by using rational cubic Ball interpolant with four parameters. The sufficient condition for the monotonicity of the rational interpolant will be derived on two of the parameters meanwhile the remaining two are free parameters that can be used to modify the final shape of the monotonic interpolating curves. The degree smoothness achieved is C1. The first derivative is estimated by using arithmetic mean method (AMM) and geometric mean method (GMM). Several numerical results will be presented including comparison with existing scheme. From the numerical results, rational cubic Ball gives visually pleasing results. © 2014 Samsul Ariffin Abdul Karim.