Nowadays, the internet is the most widely used and an effective tool for firms/organizations to reach their customers by their websites. Hence, effective design of websites helps firms/organizations to reach their aim. There are lots of design parameters that play an effective role on website design. These parameters are considered by researchers in some academic papers. However, none of the published articles takes into account both interactions among the design parameters and importance degrees of design parameters in terms of website types. Therefore, in the scope of this paper, in order to address these research gaps, an integrated multiple criteria decision making method including Delphi and DEMATEL (DEcision-MAking Trial and Evaluation Laboratory) techniques has been proposed for determining importance degrees of website design parameters. Furthermore, the website design parameters were determined based on detailed review of literature available. In addition, a new classification has been presented for websites. Finally, this paper indicates that the importance degrees of website design parameters are based on both website types and interaction among the design parameters. To illustrate the steps of the proposed algorithm, an application has been presented. (C) 2012 Elsevier B.V. All rights reserved.