The cost of Block production which largely depends on the cost of the constituent materials, affects the overall cost of construction. In this paper, a model based on mixture experiment was formulated to optimize cost of block (in Naira). Using the model, one can predict the cost per cubic meter of block if the mix ratios are given. The model can also give possible mix ratios for a specified cost. The model is tested for lack of fit using statically tool and found adequate.