The increasing complexity of construction, along with its rapid development, as well as ambiguities and gaps in the legal terms governing constructions, lack of trust in the parties regarding obligations and regulations are the main reasons of disagreements in domestic projects. These disagreements are inevitable even in contracts which are set correctly. Disagreements are costly, time-consuming and inconvenient. They also affect the price and quality of contracts. In most projects using different delivery systems, entities particularly contractors may make claims. Moreover, claims and disagreements are inevitable in Design-Bid projects, particularly in Design-Bid-Build (D-B-B) contracts, which are not commonly used in Iran. The focus of this study is the reasons for claims made in projects delivered by Design-Bid-Build (D-B-B) contracts. This study also observes claims related to consulting engineer of the owner. Accordingly, different criteria and sub-criteria are determined to prioritize by decision-making models.