Maricarmen Abascal, 87, was forcibly removed on a stretcher from her apartment of more than 70 years in September after she was unable to afford rent increases.
The company that owned the flat later offered to allow her to return at a lower rent rate - but she wasn't able to sign an agreement as she had been admitted to hospital.
"We regret to announce that Maricarmen passed away today," the Madrid Tenants' Union said in a statement, adding that her situation marked "a turning point in the history of this country".
Abascal became a symbol for Spain's housing crisis following her eviction.
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