The MA thesis presents the procedure and legislation in the field of public participation in the preparation of municipal spatial plan. We wanted to determine whether the informal modes of public participation are necessary at all or whether it is a formal way, which is statutory, enough to effectively involve the public. Based on semi-structured interview, which was conducted in ten municipalities in Slovenia and comparison of formal and informal practices of public involvement from abroad, we find that the public formally, therefore in accordance with the law, includes late. Therefore, most of the municipalities involved in our study uses a variety of informal ways in which the public had previously informed and involved in the planning process. We have also found that municipalities provide good that the public is involved sufficiently effective. We also made recommendations to simplify and improve the functioning of municipalities in the field of public involvement. We suggest making a plan of communication with the public and public exhibition and public hearing of municipal spatial plan in the early stage of its preparation. It is also important the education and training of children, which begins in kindergarten and continues in school. The public should be informed through various media, the issue should also be a special publications, which described in detail way to make remarks to the public. We also propose the introduction of planning from the bottom up, meaning that ideas drawn from the local community. The role and importance of the public lies in the fact that it is actively involved in the planning process and timely interested in him.