Interior Ministry spokesman Latfullah Mashal on Thursday said Clementina Cantoni, 32, was safe.
"Yes, she has been released. She is at the Ministry of Interior. She has spoken with her mother by phone," Mashal said.
"She is fine, she is good," he said, when asked about her condition.
Cantoni was kidnapped by four men armed with guns on a Kabul street.
Cantoni, who worked for CARE International, has been in Afghanistan since 2002 and was working on a project helping Afghan widows and their families.
She was abducted on 16 May. She was dragged from a car as she was being driven to her home in Kabul.
Her abduction prompted the Afghan security forces to launch a massive search operation.
Afghan war widows, who benefited from Cantoni's work, staged rallies seeking her release.