Abstract: This study discusses the use of C1 rational cubic spline interpolant of the form cubic/quadratic with three shape parameters to preserves the monotonicity of the given data sets. The data dependent sufficient conditions for the monotonicity of rational interpolant are derived on one parameter while the other two parameters can be further utilized to changes and modify the final shape of the monotonic interpolating curves. These sufficient conditions will ensure the existence of monotone rational interpolant. Several numerical results are presented to test the capability of the proposed rational interpolant scheme. Comparisons with the existing scheme also have been done. From all numerical results, the new rational cubic spline interpolant gives satisfactory results.