Larsson is believed to be paralysed in half his body from a stroke suffered while in captivity.
"He is in a delicate state of health and at this moment is being evaluated by a medical team in the city of Monteria. He will later be transferred to Bogota," the DAS said in a statement.
Tommy Stromberg, a Swedish embassy's counsellor, said "it's obviously a very happy day".
Stromberg said he did not know if a ransom was paid to Larsson's captors, but that Swedish police had worked closely with the DAS on the case.
Farc had sought a $5m ransom, according to the DAS.
Larsson was kidnapped in May 2007, along with his Colombian wife, from his farm that is not far from where he was released.
His wife escaped within a month of being seized, following a gunbattle between Farc fighters and the police.
Larsson became Colombia's last known foreign hostage when military agents posing as aid workers airlifted three US military contractors and Ingrid Betancourt, the French-Colombian politician, to freedom last July.
But the rebels still hold at least 22 Colombian soldiers and police for political leverage and hundreds more for ransom.
Farc once controlled large parts of Colombia but it has been hit by several setbacks in recent months.