Managing the assignment of bug report to related team or related developer is challenging and time consuming issue in large-scale software projects. In order to reduce the assignment time and to increase success of right decision making automated bug assignment approaches presented. To support automated decision making on bug assignment, researchers and practitioners propound various methods, tools and processes. Number of academic and technical sources have increased and this has brought the need to systematically categorize the current studies and practices and to provide an overview. In order to give an overview of current studies, we performed a systematic mapping study in the area of bug assignment. We searched the academic literature using several search engines (e.g., Scopus, and Google Scholar). The SM and its results are based on 93 primary studies, which were published sources like conferences (45), journals (24), symposiums (12), workshops (4) and theses (3) and others (5). As a result, approximately 46% of the primary syudies are emprical studies, and 40% used Bayesian statistics as machine learning method.