Several parties in Europe and around the world have increasingly used digital tools such as online platforms for internal decision-making, funding, communication and membership mobilization. Parties, both traditional and digital native, seem to have started a process of digitalization of their organizational structures (Gerbaudo 2018). From the Pirate Parties in Northern Europe to Podemos in Spain, La France Insoumise in France and the Five Stars Movement in Italy, over the past decade many parties have adopted participation platforms such as LiquidFeedback, Agir, Rousseau, and Plaza Podemos, allowing party members and supporters to participate directly in the drafting of the electoral manifesto and of policy proposals, in selecting party internal and electoral mandates via online votes, and to vote on strategic party decisions. So far, most of the academic attention has been focused on the impact of the use of digital technologies on party competition and campaigning, while the intra-organizational dimensions have been somewhat under-researched (Bennett, Segerberg and Knüpfer, 2018). Moreover, the literature on traditional parties and ICTs has somewhat been attracting less attention (della Porta et al., 2017; Bennet et al., 2017; Gerbaudo, 2018; Lioy et al 2019). The main purpose of this panel is to analyse how both mainstream and new parties are building their e-platforms and transitioning from traditional (offline) organizations into the digital world. To this purpose, three main sets of research questions will be discussed in this panel. First, the panel will explore how the e-platforms are regulated and which are the main issues in guaranteeing their security. The second set of questions refers to which are the main affordances allowed by the e-patform to the party members and how these e-platforms are actually used or perceived as an effective instrument of political participation. The third set of questions is related to the main consequences of these digitalization processes, both for party organizational models and electoral campaign potential. Papers cover single empirical in-depth case studies on how ICTs are shaping parties’ main intra-organizational dimensions (communication, deliberation, decision making, membership, etc.), but also papers focusing on comparative case studies and more theoretically oriented papers.