Being a newcomer is a great challenge we all face. It creates uncertainty, along with a need for new knowledge and skills in order to master a new job. This is the focus of my thesis - how newcomers learn to master their new job and how these learning processes can be characterized. Established colleagues as important knowledge sources is central, and by using the term role model, newcomers access to tacit and explicit knowledge is recognized. In relation to understanding learning as social and cultural, and not just limited to individual knowledge aquisition. The thesis also recognizes the need for understanding organizational socialization as learning and the important of informal learning processes and colleagues informally bounding in social practices at work. Thus, the thesis represent a contribution of understanding newcomers learning as both individual, social, cultural and contextual. In doing so, colleagues as knowledge sources in order to learn tacit knowledge, is crucial to newcomers learning.