Spain's Prime Minister Pedro Sánchez has called a snap general election for 28 April, after Catalan nationalist MPs withdrew support for the Socialist government's budget.
It is just eight months since Mr Sánchez took office, heading a minority government reliant on Catalan support.
Opinion polls suggest that no single party would win a clear majority. But conservatives and the far-right Vox party are expected to do well.
The Catalan crisis is still simmering.
Catalan separatist MPs rejected Mr Sánchez's budget bill after the government refused to discuss the region's right to self-determination.
Divisions were highlighted on Tuesday, when 12 Catalan separatist leaders and activists went on trial accused of rebellion and sedition over their unrecognised independence referendum in 2017.