The Spanish Civil War left the country bitterly divided
Descendants of people who fled Spain during the country's civil war are to be allowed to apply for citizenship.
The decision will allow an estimated 500,000 children and grandchildren of civil war-era exiles to seek to return.
That number is believed to include 300,000 people in Argentina alone, Spain's government says.
The measure is part of new legislation passed last year that aims to compensate and rehabilitate victims of Spain's 1936-1939 civil war.
An estimated 500,000 people died in the civil war, which left Spain as a dictatorship under the rule of the Fascist General Francisco Franco.
Descendants of Spaniards who left the country for fear of political persecution or economic hardship between 1936 and 1955 will now be able to apply for nationality before 2011.
Spain's government has said those who accept any offer of citizenship would not be required to give up their current passports.
Thousands of Spaniards fled their home country during the war, which saw the Nationalists defeat the Republican armies.
An estimated 500,000 people died in the conflict, which divided Spain sharply along ideological lines.
The country only began a transition to democracy after the death of Gen Franco in 1975.
As part of the new law, the current Socialist government will now be allowed to embark on an effort to remove Franco-era symbols and rename roads, avenues and squares.
Passing the law of restitution - of which the citizenship offer forms a part - was controversial in Spain, where opposition conservatives complained the legislation reopened old wounds.
Elderly former members of the International Brigades, the collection of anti-fascists who travelled to Spain to fight Gen Franco's forces, will also be eligible for citizenship under the new law.
Previously members of the International Brigades would have been required to give up their other nationality to accept a Spanish passport, the Associated Press reported.