This paper reports the results of a survey study involving 117 e-commerce customers. The purpose of the study was to sample the opinions of commercial web users in order to determine the critical factors that affect the effectiveness of e-commerce web sites. Web site effectiveness was measured by the intention of the users to repeatedly visit the site. Eight design factors were tested but only four were found to have significant positive impact on web site effectiveness, namely: download time, navigation, graphics usage, and interactivity. The following four factors did not seem to have any significant effects: use of frames, consistency, cohesion, and amount of advertisements. The e-commerce web site users ranked download time as the most important factor, followed by ease of navigation, graphics usage, and interactivity, in that order. The implication of these results is that some design factors significantly affect the user's intention to revisit a web site. In effect, the web sites with short download time, easy navigation, appropriate user of graphics and high degree of interactivity are more likely to attract repeat visits. Given the rapid rate at which e-commerce is gaining importance in today's business environment, the findings in this study are expected to provide helpful guidelines to both practitioners and researchers.