In today’s world of manufacturing competitiveness, quality is a prerequisite and it is no longer a differentiator. Although people in developing countries have started understanding the importance of quality in any sector, but this fact is still not clear to decision makers that a substantial amount is lost in terms of cost of poor quality (COPQ). Classically, it was considered poor quality, every product with at least one quality characteristic exceeding the tolerance limits. Consequently, the estimate of COPQ considers only products outside acceptance zone defined according to the requirements specification. In one side, the conformity with specifications aims only customer satisfaction; in other side, according to TAGUCHI, the COPQ should be calculated not only from compared limits of tolerance but also with respect to the target values of each quality characteristics. Thus, the purpose of optimization is to respect the customer’s needs, control of manufacturing processes and reducing the cost of production. The TAGUCHI approach has demonstrated high efficiency in the uni-criterion optimization process, when it is based on a single quality characteristic, but few studies have been conducted for multi criteria optimization. In this work, we propose an approach for the COPQ calculation in Moroccan pharmaceutical company by applying the TAGUCHI approach considering three quality characteristics of a coated tablet namely: Weight, Thickness and Hardness. We can arrive at an optimal quality product with a rate of poor quality reduction of 0.1€/article. Furthermore, the paper discusses the results and some advantages of this method in pharmaceutical sector.