The construction industry is one of the important and driving sectors in developing countries. In construction contracts, usually due to unforeseen circumstances, errors in the initial design, and so on... The parties to the contract face conditions that can lead to disputes and claims, and consequently, the project's claims are exposed to risk or uncertainty. The present study aims to identify the factors leading to the emergence of claims and to rank these factors in the cost-plus contract method so that employers and contractors in this field can take appropriate practical actions based on this ranking. The present study is descriptive in nature and method, with an applied objective. In order to collect data, questionnaires based on multi-criteria decision-making methods used in this research (the decision-making trial and evaluation laboratory method and the analytic network process) were utilized, which were completed by ten members of the technical committee of the Urban Development and Revitalization Organization of Shiraz Municipality, each with at least ten years of experience in the field of urban development. The collected data were analyzed using the Superdecision software. Based on the results, the factors of unilateral agendas of supervising engineers, the lack of awareness of the contracting parties about the contractual method, and the level of participation in the contract had the most significant impact, while the factors of total work cost and the quality of the completed work had the least effect on the claim proposal in the cost-plus contract method. It is suggested to create a knowledge-sharing database to prevent and avoid the recurrence of similar claims, and to establish appropriate mechanisms to prevent the re-submission of claims.