Operations Research has been applied to Renault’s supply chain and manufacturing for more than 20 years, and more recently to the scheduling of vehicle testing. OR covers a large array of topics. Often based on in-house developments, OR tools help the business make breakthroughs in terms of cost performance. OR tools are designed by a centralized OR team from the Digital Transformation Department. We present a few case studies of OR tools, based on CPLEX or CPO. Optimization issues at RENAULT are very diverse : scheduling on assembly lines and in workshops, truck route optimization, truck and container loading, scheduling of validation tests on vehicles.