The heterogeneous nature of concrete and concrete materials creates numerous variables which influence the properties of fresh and hardened concrete. In the ACI 211.1-77 method of mix proportioning, a set of tables obtained from the observation of a large number of trial mixtures are used. The relationship between the different variables in these tables are formulated into equations. Simple nonlinear regression and multiple nonlinear regression equations were used to derive the relationships between the variables involved. The regression analysis was done by using the computer program Statistical Analysis System (SAS). A computer program was written for proportioning the different ingredients of concrete using the derived equations.