This article investigates the effects of information originating from social networks on the development of interpersonal trust relations in the context of a dialysis department of a Dutch medium-sized hospital. Hypotheses on learning effects are developed from existing theories and tested using longitudinal data concerning the complete networks of trust and (informal) communication relations among employees observed at four different time points. The results support the existence of a learning mechanism operating both within dyads and through the social networks in which the dyads are embedded: actors learn to trust (or distrust) each other from their own past experience as well as from information that they receive from colleagues with whom they have regular communication.