Gioacchino Gammino, 61, was found in Galapagar, Spain, where he was living under the name Manuel.
A Google Street View shot showing a man resembling Gammino standing in front of a grocery shop was key to tracking the fugitive, investigators say.
Gammino escaped a Rome prison in 2002 and was sentenced to life in jail the following year for murder.
He was a member of a Sicilian mafia group known as Stidda and was one of Italy’s most wanted gangsters.
Sicilian police believed Gammino was in Spain, but it was the photo of him talking to a man outside El Huerto de Manu, or Manu’s Garden, that triggered an immediate investigation.
His identity was confirmed when police found a Facebook page of a now-closed restaurant, Cocina de Manu, which was located nearby. It had posted photos of Gammino wearing chef’s clothes and he was identified by a scar on his chin.
The restaurant had Sicilian dishes on the menu.
Read more: BBC