The first Western leader to visit the Libya in a decade, Aznar, was driven straight to a meeting with Libyan leader Muammar Qadhafi on arrival.
The Spanish prime minister's visit comes barely a few days after the United Nations voted to end sanctions that were imposed against Libya, following the 1988 bombing of a Pan Am flight over Lockerbie.
During his 24-hour visit, Aznar is to encourage Libya to return to the international mainstream with a "positive attitude."
At the top of the visit's agenda is the situation in Iraq and the Middle East, as well as African immigration, a major issue for Spain in recent years as it considers Libya to be a point of transit for the immigrants.
During his 24-hour visit, Aznar is to encourage Libya to return to the international mainstream with a positive attitude
Aznar is also hoping to expand commercial exchanges between Spain and Libya, now generally limited to Spanish imports of oil.
Libya's deputy foreign minister, Hassuna al-Shawsh said that during the Spanish prime minister's visit agreements in the fields of oil, electricity, industry and agriculture would be signed.
Meanwhile, government sources in Madrid said Libya had indicated it was ready to reject terrorism and respect international agreements regarding the proliferation of weapons of mass destruction.