Currently available spreadsheet software packages offer an easy to implement and user friendly platform for setting up problems involving non-linear parameter optimization. This paper presents the application of one such software "Solver" embedded in MS-Excel (TM) for quantitative interpretation of counter-current imbibition experiments on reservoir core samples. Usually imbibition tests are conducted to obtain qualitative estimates of reservoir wettability and oil recovery. This paper presents a procedure for history matching of counter-current imbibition tests that involves minimization of a user-defined global objective function with respect to various model parameters. Application of this procedure for many counter-current imbibition experiments reveals that a single dimensionless function can represent imbibition recovery history for most rock samples. Also, apparent contact angles for various samples are consistent with their expected wettability. The parameter optimization procedure presented in this paper offers a powerful and efficient method that can be modified to solve numerous reservoir and production engineering problems.