The purpose of this research is to evaluate the challenges of establishing a project management office (PMO) in construction projects. Data analysis was done by using expert questionnaires and collecting them in SPSS software and using Kolmogorov Smirnov, t-test and Friedman test. The results showed that all 6 main challenges have an impact on the purpose of the research and solving them can help to improve the status of PMO establishment. The results of the analysis of sub-challenges with the Friedman test showed that among the management challenges, the highest number related to the challenge of "insufficient project management skills" with a Friedman average of 4.64 and among the technical and executive challenges, the highest number is related to the challenge of "non-application of the hardware and software infrastructure required in the implementation of PMO" with Friedman's average of 8.09 and among the strategic sub-challenges, the most critical challenge is "inadequacy of business skills" with a Friedman average of 5.61, and among the support sub-challenges, the highest Friedman average is related to the challenge of "lack of support for project managers and PMO establishment" with an average of 8.76 and among the economic challenges, the highest Friedman average is related to "fear of rising overhead costs and being considered as an overhead cost" with a Friedman average of 3.79 and among the challenges of the stakeholders, it is related to the challenge of "not focusing on the benefits of the project" with Friedman's average of 6.44.