We present in this chapter an overview of the benchmarks aimed at evaluating the performances of Object-Oriented Databases (OODBs). We particularly focus on OCB (the Object Clustering Benchmark), which is both generic and originally designed to specifically evaluate the performances of clustering policies within OODBs. OCB is generic because its sample database may be customized to fit any of the databases introduced by the main previous benchmarks, e.g., OO1 (Object Operation 1) or OO7. The first version of OCB was purposely clustering-oriented due to a clustering-oriented workload, but OCB has been thoroughly extended to be able to suit other purposes. Eventually, OCB's code is compact and easily portable. OCB has been validated through two implementations: one within the O 2 OODB and another one within the Texas persistent object store. The performances of two different clustering policies implemented in Texas, DSTC (Dynamic, Statistical, Tunable Clustering) and DRO (Detection & Reclustering of Objects), have also been compared with OCB.