[1][2] Despite Artur Mas campaigning to win an absolute majority of seats, Convergence and Union (CiU) suffered an electoral setback which had gone largely unnoticed by opinion polls.

The People's Party (PP) and Citizens (C's) benefitted from the electoral polarization between the pro-independence and anti-independence blocs, scoring their best results until then, with 19 and 9 seats, respectively.

[a] Voting for the Parliament was on the basis of universal suffrage, which comprised all nationals over 18 years of age, registered in Catalonia and in full enjoyment of their political rights.

[5] The 135 members of the Parliament of Catalonia were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which included blank ballots—being applied in each constituency.

[4] The president had the prerogative to dissolve the Parliament of Catalonia and call a snap election, provided that no motion of no confidence was in process and that dissolution did not occur before one year had elapsed since a previous one under this procedure.

In spite of this, the relationship between both parties quickly deteriorated after the 2011 general election, as a result of Mas asking new Spanish prime minister Mariano Rajoy for greater fiscal autonomy for Catalonia.

[16] Mas' move was criticized as an attempt to try to funnel the popular support for independence seen in the September demonstration into an absolute majority of seats in the election.

The table below lists opinion polling on the perceived likelihood of victory for each party in the event of a regional election taking place.

The table below shows registered vote turnout on election day without including voters from the Census of Absent-Residents (CERA).