Introduction: Due to a lack of techniques there is only some data of testing mechanical influence on chondroc-tyes grown in 3-D tissue-culture over several months. The authors developed therfore a new perfusion-chamber to study these mechanical factors in in-vitro tissue culture. Methods: A pneumatic computer-controlled bioreactor which allows the application of pressure between 0,1 – 2 MPa in frequencies less than 1 Hz over a period of several months was developed. The reactor is made of stainless steel and closed to the surrounding atmosphere with a steril, flexible and pressure resistant layer of film. 8 scaffolds with a maximal diameter of 10 mm and a maximal height of 15 mm can be studied independently in respect to pressure parameters. A continous flow of medium allows an excellent nutrition, temperature is controlled by a closed heat unit. In a first system three bioreactors are used simultaneousely. Results: In first cultures of tissues over a period of three months sterility was well contained without any mechanical problems. With a high degree of automation a nearly uncontrolled running was possible.