"Bolivia needs partners, foreign investors, but not owners of our natural resources," Morales told reporters on Wednesday in Madrid where he was stopping as part of a continuing tour that includes visits to France, Belgium, South Africa, China and Brazil.
"My government ... is going to exercise its property right over its natural resources."
He also said that his government will not tolerate foreign companies that do not respect the law in Bolivia.
"We're going to have a radical attitude with all those oil companies that do not comply with Bolivian law, those that do not pay taxes, those that are smugglers," he said.
Speaking after meeting Jose Luis Rodriguez Zapatero, the prime minister of Spain, Morales said he had told him that Spain would pardon nearly all of Bolivia's debt to the country in exchange for investment in education programmes, a measure the Spanish premier has been keen to apply to many Latin American countries.
Bolivia's debt to Spain is estimated at US$120 million.
"This is a great relief for me," Morales said. "We want to put an end to our country's illiteracy rate."
Morales then met King Juan Carlos at Zarzuela Palace on Madrid's outskirts.
Morales arrived at Madrid's international airport aboard a Venezuelan jet provided by Hugo Chavez.
"We're going to have a radical attitude with all those oil companies that do not comply with Bolivian law"
Evo Morales, Bolivia's president-elect
On Thursday, Morales flies to Brussels.
In the morning, he held talks with Miguel Angel Moratinos, the foreign minister of Spain, Jose Montilla, the industry minister, the Spanish employers' organisation and representatives of the Spanish-Argentine Repsol YPF oil company.
Speaking later, Montilla said he was confident his country could maintain smooth relations with Bolivia.
He said that international energy companies operating in Bolivia "may see some changes in the rules of the game", but also noted that Morales was aware of the role that Spanish and international companies play in job and income creation across Bolivia.
Che Guevara path
At one point during the news conference, he said he still could not believe that he was elected president and he compared his movement with that of socialist icon Ernesto "Che" Guevara.
But unlike Guevara, he said, he would work democratically for change, based on "votes, not on bullets".
Evo Morales (L) with King Juan
Carlos (C) at the Zarzuela Palace
Morales's campaign promises to nationalise Bolivia's oil and natural gas was high on the agenda of his visit.
The tour is aimed at drumming up support for his incoming government, the first headed by an Indian in Bolivia's 180-year history, and also to show that he can hold his own on the world stage.
Spain's Repsol YPF, which has invested US$1.08 billion in Bolivia, is one of the main foreign energy companies operating in the country.
Bolivia's proven and potential reserves total 53.3 trillion cubic feet of natural gas is second only to Venezuela in South America, according to the US Department of Energy's Energy Information Administration.