Considering the present business competitive scenario, the automotiveindustry is under pressure to achieve higher productivity. A high level ofperformance and quality standard could be achieved through improvingthe Overall Equipment Effectiveness (OEE) of the equipment in anautomotive industry. Thus, the aim of this study is to investigate theperformance measurement through OEE theory in an Iranian automotiveindustry. Data and basic information collected from the ComputerizedMaintenance Management System (CMMS) of the automotive assemblylines. In this case study, two different assembly lines such Peugeot andSports Utility Vehicle (SUV) were studied. The results indicated that theindices such availability rate, performance and quality for Peugeotassembly line obtained an OEE value of 0.99, 0.70 and 0.38,respectively, and, these indices for SUV assembly line obtained as 0.99,0.39 and 0.53, respectively. Statistical analysis results of net operatingtime parameter for two assembly lines revealed that there is significantdifference in the confidence level of 5% (P-value < 0.05). In addition, theOEE index for Peugeot and SUV assembly lines gained 0.27 and 0.21over a period of one year. Consequently, to improve the OEE in theautomotive assembly lines, managing the time losses by systematicplanning of manufacturing and the implementation of Total ProductiveMaintenance (TPM) are suggested.