This paper surveys the literature on university patenting. From the point of view of the economic theory of patents, it is argued that patenting knowledge developed by university researchers is paradoxical: patents are normally intended to stimulate knowledge development by providing property rights, but universities operate also under a different incentive scheme, i.e. they receive public funds to perform socially useful knowledge. In the debate surrounding the so-called Bayh-Dole Act in the USA, it has, however, been argued that patents on university inventions may be necessary to stimulate technology transfer from universities to private firms. The first part of the paper addresses two major questions. First, what is the economic logic of Bayh-Dole, and, second, what were the effects on universities and the knowledge they develop? In the second part, the paper addresses the issue of whether 'Bayh-Dole-like' legislation would be beneficial for European countries. In a number of European countries, a suggestion has been made that this could enhance knowledge transfer from the public to the private sector. Using a new database resulting from a survey among patent inventors in six European countries, an assessment is given of the degree of university patenting in Europe. Because university researchers are often involved in patented inventions without the university being listed as a patent applicant, statistics based on the patent office databases alone often underestimate university patenting in Europe. The paper ends with a discussion of how this 'European practice' of university patenting affects public–private knowledge transfer in Europe, and how this compares to the effects of the Bayh-Dole Act in the USA.