Purpose – The purpose of our study is to investigate the characteristics and interrelations between informal communities of practice and formal networks of practice and its consequences for learning and new knowledge at work. Methodology – A case study was conducted in a Norwegian bank using qualitative explorative studies and in-depth interviews with financial advisers and their leaders. Findings – Our findings demonstrate that in the absence of integration efforts via a network of practice, multiple communities of practice to ensure knowledge flow is not enough. By the same token, it is possible for new knowledge to be accepted where a community of practice functions cohesively in a singular form in close interrelation with network of practices, but only when both communities of practice and network of practices are supported by a participatory leader. Originality – There are no studies to our knowledge that investigate the interrelations between informal communities of practice and formal network of practices. Research limitations – The total of 30 in-depth interviews might call for further studies. Also, studying a Norway bank alliance does not account for cultural differences between countries.