Аннотация:Even though the importance of knowledge transfer within project-oriented organizations is frequently emphasized in the recent project management literature, in practice, knowledge transfer only takes place to a rather limited extent. Based on an in-depth case study, findings from a company, in which several initiatives to promote knowledge transfer between five full-time project managers were taken, are presented. However, the initiatives did not bring the expected outcome. The organizational subculture encompassing project managers may explain reluctance in involvement in knowledge transfer and in sharing of lessons learned. Based on Schein's notion (1987) six basic underlying assumptions in the organizational culture that limit knowledge transfer are identified. Further, the authors propose an interaction paradigm underlying project managers' interactions.