Implementing an information system (IS) project in a public sector can be very risky, expensive and difficult (Ahmad & Othman, 2006-7). This is because the development of IS project especially in the public sector is exposed to the problems such as ineffective project management, technology failure and inadequate funding. One possible solution to these issues is by identifying the critical success and failure factors of the project because the knowledge and understanding in these two areas have great importance for project management effectiveness (Bellasi & Tukel, 1996). This study is focusing on the Malaysian public sector information technology (IT) staff in the context of their perceptions on factors that contributed to IS project success and failure. In addition, this study examined how attribution theory by Weiner (1980) may account for differences between the IT support group (SG) and the IT management and professional group (MP) in terms of their perceptions on the relative factors contributing to the success and failure of IS project. A set of questionnaire was formed based on a list of IS project success and failure factors identified from previous literature. Questionnaires were distributed to 149 IT staff in the Information Management Division in Public Service Department, Putrajaya. Only 88 returned responses were usable for data analysis. The results indicated that the IT staff in general view team member commitment, quality team member and use of appropriate technology as the key factors that contributed most to IS project success, and view implementing ineffective project management, lack of clearly stated project's goals and objectives, and top management support and active commitment as the key factors to IS project failure. No significant differences in the perceptions of success and failure factors were observed between the IT support group (SG) and IT management and professional group (MP). Results obtained were inconsistent with the Malaysian organizational culture who view leadership and management as most importance; and both IT staff groups deny credit for project success neither responsibility for project failure.