Party politics in multi-level systems has become a growing research field in political science (see Hough et al, 2003; Hough and Jeffery, 2006), but has rarely focused on comparing structures of multi-level party competition. Regional party competition is particularly important in political systems where state decentralisation has significantly shifted the electoral and coalitional incentives available to party actors, whether statewide or nonstatewide. This paper will compare structures of party competition in the Spanish regions, using three principal dimensions of analysis: electoral support for statewide parties in regional elections; patterns of coalition formation at regional level; and patterns of alternation in regional government. The paper finds that multi-level party competition in Spain displays 'vertical' (central-regional) and 'horizontal' (inter-regional) incongruence (Thorlakson, 2006; 2007). This incongruence has never undermined party competition at central level, due partly to the weakness of systemic linkages between regional and central party systems. The main exception is Catalonia, where systemic linkages with Spanish politics are so strong that all parties (statewide and non-statewide) have sought to pursue a strategy of coalitional congruence. Divergent patterns of regional party competition have encouraged some regional branches of statewide parties to become more autonomous from the central leadership, both in their electoral strategies and coalitional choices, while others have remained closely integrated with the central leadership. This has significantly reinforced the degree of internal asymmetry in the multi-level organisation of statewide parties in Spain.