Omar bin Laden, a self-described pacifist, made the request immediately after arriving at Madrid airport yesterday on a flight from Cairo that had been going on to Casablanca in Morocco.
"He has asked for political asylum," Interior Minister Alfredo Perez Rubalcaba said, without specifying on what grounds the request had been made.
"We know he has travelled to several countries in Europe, that he has a home in Cairo although he travels on a passport from Saudi Arabia," he said.
Under Spanish asylum rules, the ministry has 72 hours to make a decision, and the petitioner has a right of appeal.
Omar, 28, will remain at the airport while his request for asylum is processed, an interior ministry spokesman said.
Authorities in Britain turned down a request in April from Omar bin Laden for a settlement visa. At the time he said he wanted to live in England with his new British wife, Zaina Alsabah bin Laden, 52, formerly known as Jane Felix-Browne.
The British embassy in Cairo said it had based its decision on fears that his presence in the country would cause "considerable public concern".
Omar is the fourth of 11 children born to his father`s first wife, and he is one of 19 children Osama bin Laden has fathered.
In an interview broadcast on CNN in January, Omar urged his father to give up violence.
"I try and say to my father: `Try to find another way to help or find your goal. This bomb, this weapons, it`s not good to use it for anybody`," he said.
He also said he had not spoken to his father since 2000, when he walked away from an al-Qaeda training camp in Afghanistan with Osama`s blessings, and does not know where the al-Qaeda leader is.
Osama bin Laden has claimed responsibility for the September 11, 2001 attacks in the United States that killed more than 3,000 people.
In 2004 Spain suffered one of Europe`s deadliest attacks when bombs planted by Islamic extremists inspired by al-Qaeda and angered by the country`s participation in the US-led invasion of Iraq exploded on packed commuter trains in Madrid, killing 191 people.
