Contemporary scholarship on intra-party democracy pays a great deal of attention to aggregative procedures like primaries or membership ballots but widely ignores deliberative procedures within parties. This article begins by highlighting why scholars should care about deliberation within parties, discussing several functions intra-party deliberation is said to serve in the democratic theory literature. It then goes on to explore the deliberative credentials of political discussion between party members, drawing on group interviews with party members in two Social Democratic parties in Germany and Austria. Two issues are investigated: the preconditions for deliberation among party members and their justificatory patterns. The results of the analysis suggest that parties can be genuine vehicles of deliberation, and thus point towards a research programme on intra-party democracy that differs quite starkly from that which prevails.