Nowadays companies face continuous changes. Every change a firm face has to be carefully addressed by everyone in the organization but especially by leaders and the managerial team. However these changes not always produce monetary benefits. A change on the IS might increase productivity in one business area but it might not represent profit to the whole company.

There are several change studies which can be used as guide by leaders when im-plementing a change. However none of these theories consider the possibility to improve efficiency as a result of the change. Neither to assure that after the IS change implementation the company‟s profitability increases. The theory of con-straints (TOC) is a useful tool which covers both of the issues mentioned before.

This paper will combine several change theories with the theory of constraints. With this mixture of ideas we want to show leaders a new procedure on which they can relay on when dealing with the process of an IS change. This procedure should assure an increment on the productivity produce after the change. But also consider an addition to the company profitability.

We studied three change related theories. We then revised the TOC and we com-pared all this recollected information with the way six leaders handled IS changes in their companies. These five companies were Dell, Cisco Systems, Desca, Ericsson, and Nortel.

At the end we were able to identify critical success factors which any leader should consider when facing an IS change. These factors cover from the beginning of the IS change, the implementation of it and finally the way to make this change maximize the business performance.