Since the interest in mobile communication sector is increasing day by day, it makes traffic volume problem more important. There are different works focused on developing more secure and qualified service for professional users and companies. The Professional Mobile Radio (PMR) system, specially developed for professional users in the communication sector, can be offered to the service of professional users and companies with the desired specifications. With the Tetra system, which is one of the PMR systems, users can get more advanced technological services than the conventional PMR systems. Cell selection algorithms have a great importance for these systems which are needed for more reliable, private and seamless communication. In this thesis, we present two novel cell selection algorithms that can be applied to the Tetra based PMR systems. In these algorithms, both the received power of users and the fair distribution of the overall system are considered. Performance evaluation of algorithms with different traffic characteristics is considered in different environments.