Response surface methodology (RSM) is the most popular optimization method used in recent years. There are so many works based on the application of RSM in chemical and biochemical process. On the other hand, few articles were published about the limitation and usability of it. In this paper, we looked at some of the RSM articles published during the last few years. We tried to identify common mistakes made in the application and the limitations of RSM. We asked ourselves two important questions. These questions are "Can RSM be used for optimization of all chemical and biochemical processes without any limitation?" and "Is RSM usable for other purposes (determination of reaction kinetics, stability or evaluation of kinetic constants etc.) in addition to optimization?". We were able to answer these questions based on the observations obtained from reviewed articles. We believe that the answers will be helpful for researchers, who will use RSM in their future studies. (c) 2005 Elsevier Ltd. All rights reserved.