The transfer of research results is one of the ERCIM institutes' main assignment today in addition to basic and applied research in Computer Science and Mathematics. The creation of high tech companies by researchers is an effective way of achieving such transfer. The links these companies maintain with their "mother" research institution, which in a certain way "labels" the companies, has been identified as an important factor in guaranteeing their survival. A death-rate of 10% instead of 50% for the general case has been observed for such companies. Over the last years, ERCIM members have played a pioneering role in creating small and medium high-tech companies. ERCIM is represented in thirteen European countries and its members have spawned over 90 companies. The policy of technology transfer depends on the specific situation of each institution and each country. The following articles will try to give an overview of the ERICM institutes' technology transfer policies, they will show how knowledge is transferred from ERCIM sites to industry and how spin-off companies operate on the market utilising knowledge generated in the mother institute.