Poor cost performance is a typical problem in construction projects where few projects were completed 
within the original estimated cost. The previous researches (literature) show that up to 90% of construction projects 
suffer cost overrun with amounts ranged from 5% to 200%. This paper first utilizes a literature review to identify 
cost overrun causes and categorizes such causes based on stakeholder, country, and project type. Secondly, an indepth review was conducted to identify the contractors' cost overrun root causes. Thirdly, contractors' gaps and 
shortage of cost management processes have been identified. Finally, guidelines were concluded to resolve the 
identified gaps and enhance cost performance. The research conclusions depict that the top five cost overrun causes 
were inflation and fluctuation of construction resources, inaccurate cost estimates, poor cost control, poor owners' 
financial status, and work scope change. In addition, this research manifests that two top contractors' related cost 
overrun factors, inaccurate cost estimate, and poor cost control, were deemed the main elements of the cost 
management system. Another major contribution of this research is addressing the gaps in cost management 
processes to pave the way for future studies on identified gaps