The political opposition groups that organized the rally said Spain was stumbling toward "an economic and social emergency" that would only be worsened by cutting people off from healthcare and higher education.
They also decried reforms to the Spanish national pension system as a thinly disguised move to privatize the program.
The pre-May Day rally drew about 9,000 people, Madrid police told El Mundo, although organizers said the number was more like 40,000. Similar smaller protests took place in Barcelona and other cities.
Celebrity Families of 2014 [PHOTOS]