Background: Nowadays, projects become the common way of working in manycompanies. Knowledge management is important for efficient project management.Knowledge transfer in project-based environments became an attractive and importanttopic for study. Various barriers and challenges will appear during the process ofknowledge transfer in projects. Lots of authors thought the barriers of knowledgetransfer in project are negative, while others mentioned that some barriers may havepositive aspects. We called these two kinds of barriers “positive barriers” and“negative barriers” in this thesis. Purpose: The purpose of this thesis is to understand knowledge transfer inproject-based environments. Specifically, we aim to explain that barriers ofknowledge transfer in projects can be both negative and positive. Method: Due to the special time period and activity limitation, we chose case studyto gain the empirical data. When choosing the sample, we used the conveniencesampling. The sample chosen is a project team in Ericsson of Linköping. The projectmanager we interviewed has worked in Ericsson since 2004 and with his presentproject team for four years. He has already done more than fifteen projects, so he hasenough experience in projects for our study. We combined both inductive anddeductive approach strategies to analyze our thesis. Result: This thesis has answered the questions in the part of specified questions andreached the thesis purpose. It has explained the notion of knowledge transfer inprojects and its related barriers. It interprets how both negative and positive barriersaffect knowledge transfer. Furthermore, this thesis points out some suggestions forimproving positive barriers and reducing negative barriers.