"The president of the republic informs his compatriots that he has designated as foreign minister Fernando Araujo Perdomo," Mr Uribe's office said in a statement.
Fernando Araujo had been held hostage by the Revolutionary Armed Forces of Colombia (Farc), a far-left guerrilla organisation.
He escaped during a military attack on the camp where he had been in captivity.
Maria Araujo, stood down on Monday after her brother Alvaro Araujo, a senator, was jailed last week on charges of collusion with illegal paramilitaries and orchestrating the kidnapping of a political rival.
Eight Uribe-allied federal politicians have now been jailed for allegedly benefitting at the ballot box from collusion with paramilitaries.
Paramilitaries are responsible for some of the worst massacres in
The alleged ties between Uribe's political backers and the paramilitaries, has complicated the president's international appeals for help to fight rebels and drug traffickers and modernise the judicial system.
Uribe is counting on billions of dollars in aid from the
Some US Democrats are now calling for $700m in mostly military aid that
Patrick Leahy, chairman of the senate subcommittee that controls aid to
"American taxpayers deserve assurances that the Colombian government has severed links to these terrorist groups."
The EU's delegation in