"We do not have evidence that Spain has been spied on ... but we are calling in the ambassador to get information," Rajoy said after an EU summit dominated by the growing scandal over US intelligence activities in supposedly friendly countries.
Spanish media reports said the US National Security Agency had spied on several members of the government and politicians, including former Socialist Prime Minister Rodriguez Zapatero.
Germany called in the US ambassador to Berlin earlier this week after reports the Chancellor Angela Merkel's mobile phone had been tapped.
"Spying between friends, that's just not done," Merkel said.
The 28 European Union leaders earlier approved a statement which said they valued the relationship with the United States but it had to based on trust and confidence, especially in intelligence matters.
France and Germany are to lead efforts to reach a new understanding with Washington by the end of this year.
Rajoy said that for the moment, Spain would not join Berlin and Paris in this effort and reiterated that intelligence issues were the responsibility of national governments, not of the EU.