EN
The article shows problems of trust in building, development and functioning of scientific units with reference to given R & D networks. Three networks of scientific units which have different origin, potential and activity profile are discussed. The article refers to and is a continuation of an earlier publication titled “Trust in R & D network of scientific units. The role of originator” published in a quarterly “Management Science”. Case studies in this article show the importance of trust in different phases of development of a scientific unit as a key factor influencing network activity and illustrate the influence of conditioning on its level.