The use of internet and other communication technology has become predominantly common in the life of normal sighted users. In order to have a fair level of equality in the society, blind people must also be able to use these facilities with equal ease and effectiveness Many governments decided to implement e-Government applications to enhance the delivery of information and services to its citizens, residents and businesses. These e-Government applications were carefully designed with the help of international standards to serve the whole group of population and especially people with disabilities. However, recent studies showed that the acceptance rate of these e Government applications among the community, especially between people with disability, is not up to the expectations. The aim of this research is to investigate the accessibility issues faced by blind people while interacting with online services like e-Government portals Owing to the nature of content and the importance of information which is to be delivered to the whole country, the accessibility standards of such portals are of paramount importance. It is this idea of evaluation of such websites for special category of blind people that has been the main focus of this thesis. The main aim of this doctoral research is to discover any accessibility problems that could be faced by people with blind users during online interaction and not covered in accessibility standards. A real example of online interaction is the e-Government portals. This research followed a rigours tri-staged evaluation process for a selected e-Government portal (Saudi Arabian portal) to analyse the accessibility issues faced by blind people. The aim of this evaluation process is to understand the cognition and perception of a blind user while interacting with a web-based environment. The first step of the evaluation process was to verify the level of adherence of the selected portal to the Web Content Accessibility Guidelines (WCAG). The second stage includes a detailed experimental exercise with a number of blind people following the task- oriented approach. The third step of the evaluation process was a detailed interview with web designers to analyse the problems faced by blind participants in the experimental exercise. Thereafter, cognitive-based solutions were proposed to improve the accessibility of online interaction for blind users and fill the gap in the accessibility standards. The introduction of navigational landmarks and the insertion of virtual map description improve the navigation and hence the performance of blind users. The proposed solution has been tested with a separate group of blind users to validate the research findings and to ensure the desired level of accessibility of the e-Government portals is achieved.