The reactor with a rotating bed, BIOSTAT® B plus RPB, has been developed in cooperation with the Zellwerk Corp. With the use of recently developed materials, and the industry proven control techniques of Sartorius, this bioreactor is an ideal tool to grow adherent cells. The perfusion mode and the optimum process control of all key parameters allow the cultivation on a long term basis with high cell densitity. The system with the rotating bed, based on specially doped disks of Sponceram® with a macro/micro porous structure, allow a tissue-similar growth, and is especially developed for the production of proteins as well as for the proliferation of primary cells. The sheer-stress-free supply of the immobilized cells with oxigen and nutrients is guaranteed by the rotation of the carrier through the media and the gas atmosphere. The integrated touch-screen of the controlling unit allows an easy and intuitive access to all process parameters, and monitor the digital calibration routines for sensors and pumps. With the trend-display it is possible to monitor the "wellbeeing" of the cells based on up to six parameters. The package includes, in addition to a selection of ceramic carriers for specific applications, also the SCADA Software optimized for the documentation and evaluation of all process data.