Canadian parliamentary party groups present a mixed picture of discipline and cohesion. Canadian House of Commons votes are tightly disciplined by party with less dissent than in Britain. Yet traditional Canadian parties have been quite ideologically heterogeneous, with cohesion based more on personal relationships and loyalties than shared ideological bonds. The arrival of new parties in 1993 has challenged this traditional pattern, but the differences between older and newer parties are more in degree than kind. This article hypothesises that these trends are linked to the fluid membership base of Canadian parties, which tends to reinforce central power. The result is disciplined and somewhat cohesive parties, but with a lack of ideological direction or consistency.