Diversity on COTS selection is causing that certain companies spend large amount of time and effort evaluating those COTS for integration within their custom made systems. This evaluation is most of the times based on de-facto rules and techniques that unfortunately may lead the company in choosing the worse or not the best component for its system. This research gives an interpretation on how to evaluate COTS making use of two different methodologies for software selection and decision making respectively. The purpose is to present how the DESMET methodology along with the AHP methodology can be combined in such a way that COTS selection would be easier and more accurate than before. This new evaluation approach will make COTS selection less human dependable and more straight forward, providing with the mean for ranking the different alternatives in a numerical way so deciding becomes more empirical base and less human base.