E-service evaluation is a complex problem in which many qualitative attributes must be considered. These kinds of attributes make the evaluation process hard and vague. Cost-benefit analyses applied to various areas are usually based on the data under certainty or risk. In case of uncertain, vague, and/or linguistic data, the fuzzy set theory can be used to handle the analysis. In this article, after the evaluation attributes of e-services and the fuzzy multi-attribute decision-making methods are introduced, a fuzzy hierarchical TOPSIS model is developed and applied to an e-service provider selection problem with some sensitivity analyses. The developed model is a useful tool for the companies that prefer outsourcing for e-activities. It is shown that service systems can be effectively evaluated by the proposed method. (c) 2007 Wiley Periodicals, Inc.