Party regulation in new democracies in general, and in the Spanish political system in particular, has not been a matter of concern until very recently. So far this topic has been persistently neglected by political studies, which considered it an issue for academic lawyers. However, this attitude has recently started to change, since party law has become an institutional factor that might affect strongly the dynamics of party systems, as well as foster intra-party democracy. This paper explores the way political parties have been regulated not only in the 1978 Constitution (section 1), but also in the main laws regulating party foundation, organization, dissolution and, not least, funding. The empirical part of the paper tries to identify, using process tracing methods, the main factors laying behind party regulation and each party funding reform adopted in Spain. The main conclusion is that such laws have had a mixed impact on Spain's party political life.