Abstarct: The purpose of the current research is to evaluate the implementation barriers of value engineering in small and medium companies. The statistical population includes experts in the auto parts manufacturing industry. The sample size is 10 randomly selected people. The researchers used a researcher-made questionnaire. The research analysis was conducted in two stages. In the first stage, implementation barriers to value engineering have been collected through interviews and research literature. In order to evaluate and screen risks for managers, the Delphi technique has been used in two stages. In the next step, Dematel's technique has been used in order to find the cause-and-effect relationships of implementation obstacles in value engineering. The results of the research indicate that 34 primary barriers were extracted from the interview, and 20 implementation barriers were finalized using the Delphi technique. In Dematal's technique, nine net-effective criteria and 11 net-effective criteria have been identified. Failure to pay attention to employee motivation has the greatest impact, and lack of organization of contracts has the greatest impact.