The concept of internal marketing appeared in literature and in the focus of researchers rather late, only in the 1970s, despite the obvious positive correlation between implementation of the concept of internal marketing and the market success of the implementing organizations. In for-profit organizations this concept has been well researched, while in the non-profit sector there is still room for improvement, as the transfer of marketing principles from business organizations to the non-profit ones is a complex process. In the Republic of Croatia, research in the area of internal marketing has been mainly carried out in for-profit organizations, while such research , according to the author's knowledge, is rather scarce in political parties. Therefore, this thesis is the result of efforts to point out the extent of internal marketing implementation in an important social category – political parties, but also of a desire to raise awareness of the importance of implementing internal marketing in political parties, considering the benefits it could bring. The research carried out for the purpose of this thesis, which examined the party members’ views on the extent of internal marketing implementation, confirmed the opinion that implementation of internal marketing in political parties in the Republic of Croatia is at a moderate level. It also pointed to the need for additional efforts by all stakeholders involved in this process – from researchers who should acquire additional knowledge on this subject to leaders of political parties who should implement existing knowledge in this field into the work of political parties. All this needs to be done so that they could make progress in this area with the ultimate objective of obtaining better election results and stronger connection of party members with the policies they represent. Organizing informal meetings (entertainment, sporting, cultural, educational, training, gastronomic and similar events) is a good solution to the problem of low levels of member satisfaction, with informally generated information. Party leaders should therefore increase their efforts in this segment. Party leaders should also adapt their conduct to members’ expectations and change policies as necessary, which would certainly lead to increased satisfaction of party members and consequently to better election results.