Abstract: The main objective of this research is to recognize and categorize the most severe risk factors affecting the implementation of construction projects for public client in Jordan. A questionnaire was prepared depending on the literature review and 53 risk factors were identified and categorized into four groups (technical, management, financial and market and political, social and environmental). A survey was carried out and included 108 participants representing clients, consultants and contractors involved in the implementation of public construction works in this country. The analysis of results showed that 8 significant risk factors are technical related, risk factors are management related, risk factors are financial and market related and factors are related to political, social and environmental group. Out of the 53 factors, 20 of them found to have significant effect. The top 10 significant factors are; changes of design by different parties, management problems related to the contractors, design and contract documents errors, conflict in contract documents, lack of planning and budgeting of project, financial problems suffered by contractors, inappropriate communications between client and other parties, loss due to bureaucracy and late approval, material wastage on site rework due to labor mistakes.