Transport and other public services across Spain have faced serious disruption in the first general strike for 14 years called by the main unions over housing and the high cost of living.
Demonstrations were also planned later on Wednesday, with the biggest protests expected in Madrid and Barcelona. Spaniards are due to vote in parliamentary elections on 29 November.
The head of the big UGT labour union, Pepe Álvarez, said the strike was a success with "massive" participation, while Unai Sordo of the CC OO union said turnout was "very significant."
However, the Spanish Confederation of Business Organisations said participation was "low and uneven", depending on the areas and sectors involved.
Some of the biggest disruption on Wednesday was seen in the main industrial hubs of Madrid and the north-eastern region of Catalonia where traffic was halted on several main roads.
The interior ministry said dozens of people were arrested for a variety of incidents and Spanish reports said estate agencies had seen attacks on their offices.
The strike was triggered by widespread protests over affordable housing and rising living costs, after the eviction of 87-year-old Maricarmen Abascal from a flat in Madrid where she had lived for seven decades. She died in hospital weeks later.
