Opening-up processes of candidate selection is often viewed as a means for political parties to regain legitimacy, and perhaps more crucially, members and voters. Despite a widespread belief that citizens want more democracy, including within parties, little research has questioned what sort of opening-up is desired—e.g. open or closed primaries—if at all, and by what type of citizens. Using data of the 2014 PartiRep voter survey in Belgium, we examine the diversity of preferences regarding candidate selection, and the extent to which preferences for open or closed primaries relate to voters’ participation in party organisations. Given the diversification of party affiliation types, we operationalise participation through two distinct variables: the formal party membership status of the respondents, and their party activism. We show that both membership and activism influence individual preferences, and that their effects are in fact conditional upon each other. Findings also raise crucial issues regarding the consequences of the multiplication of affiliation modes, the motivations and direction of intra-party reforms, as well as feed the debate on their expected versus genuine consequences. ; SCOPUS: ar.j ; info:eu-repo/semantics/published