When a new technology is invented to solve a certain problem, communication occurs between inventors taking part in the process. With the advancement of information and communication technology, communication of explicit knowledge between individuals in distant places has become far easier than ever before. But what about in cases where highly intensive and wide-ranging communication is required and tacit knowledge needs to be exchanged? For instance, during invention activities, what is the distance across which inventors communicate and exchange tacit knowledge? This study uses inventors of patented biotechnology inventions as samples, measuring the distances between the home addresses of co-inventors. The distance across which explicit knowledge is communicated is measured in terms of the distance between an inventor's address and the address of a research institution to which a research paper cited in the relevant patent is attributed. The two distances are then compared. It has been found that the median inter-inventor distance is some 32 km, far shorter than the median communication distance of 4,300 km. This suggests that, even in this age of globalization, the presence of knowledge agglomeration within or nearby a specific country or region remains important to the enhancement of the industrial competitiveness of that country or region. The findings will serve as a useful reference for policy-makers in the formulation of science and technology policies as well as regional policies.