Purpose: The main objective of the study is to indicate the role of trust in the processes of knowledge diffusion of IT professionals. This includes the identification of individual types and components of trust impacting the knowledge exchange between intellectual workers, as seen from the perspective of knowledge agent groups involved in its circulation, and in sub-processes constituting the transfer of knowledge, as well as in generation of specialists. Design/Methodology/Approach: The procedure for obtaining empirical data consisted of three stages: the direct semi-structured individual interview, focus group online interviews (FIGO), computer assisted telephone interview (CATI) and computer-assisted web interview (CAWI). The hypotheses were tested with a test of significance for Spearman’s rank-order correlation coefficient and the Wilcoxon-Mann-Whitney test. Findings: Trust is a factor in knowledge diffusion among intellectual workers and its importance depends on the groups of knowledge agents participating in it. Trust is most important in the exchange of knowledge among professionals, then in the circulation of knowledge between specialists and co-operators, and the least important – in the dispersion of knowledge between knowledge workers and the organization’s personnel. Regardless of the group participating in the circulation of knowledge, the foundation of trust is competence-based trust, supported by benevolence-based trust. Practical Implications: The presented considerations provide specific indications as to which components of trust to develop due to the sub process of knowledge diffusion, and knowledge agents involved in the circulation. Originality/Value: This study’s main contribution is filling the existing research gap regarding the impact of trust on the flow of intellectual workers’ knowledge. The work has theoretical and practical contribution to research on the diffusion of professional knowledge. It organizes the theory and formulates practical guidelines for the formation of trust as a factor of knowledge dispersion.