The increase of international competition motivated most of the organizations to create useful shared mutual cooperation with supply chain partners since they understood that cooperation and collaboration of supply chain partners is the prerequisite for the increase of reliability level and the decrease of risks and also the enhancement of innovative qualities and profitability of the companies in recent competitive and dynamic market. Integration of supply chain is an important strategy in creating cooperation and collaboration among different elements of supply chain, and plays a vital role in the enhancement of performance of the companies in supply chain. The objective of the present study is to investigate the effect of supply chain integration on the performance of car part manufacturing companies. Current study follows a descriptive, analytical approach in which the correlation between the variables of sample under study is investigated. This sample includes 81 company which produce car parts with a grade A of SAPCO Company. Samples were selected through census in the initial phase. However in the second phase sampling was done through improbable and judgmental sampling. In order to testify hypothesis PLS method was used. The result of this study indicates that there is a direct effect between supply chain integration and improvement of operational performance of companies under investigation. Manuscript profile