Companies employ the World Wide Web (Web) to gather and disseminate information to and from actual and potential customers and increasingly for end-consumer business transactions through Electronic Commerce (EC). Online barriers limit or eliminate Web accessibility for many potential customers with access challenges. It is difficult to establish, develop and manage relationships with potential customers if they cannot access the company's Web site for information, let alone to place orders or request services. This study evaluated the accessibility of the top 100 2001 Fortune 500 company Web sites. An accessibility validation program quantified the number and severity of accessibility errors and problems for each site. Results indicated that the majority (71%) of the Fortune 100 Company Web sites had accessibility problems and that many of these problems were severe enough those firms should consider it a high priority to correct them. Additionally, many errors and problems should be fixed as a matter of good programming style as well as general interface and usability principles. The bright side is there were actually few types of errors across all 100 Web sites and most can easily be amended to make sites more accessible and usable for all potential customers. This study illustrates the need for companies to examine the accessibility of their Web sites and bring them into compliance with ADA and other guidelines and requirements. Suggestions for improving accessibility of Web sites are provided.