One of the three found the statue in his garden and asked the other two to sell it, police say.
Greek police have charged three men for trying to sell a Roman-era statue of the Greek goddess Hecate.
The marble statue is believed to have originated from the second or third century AD, when Greece was part of the Roman Empire.
Authorities in Thessaloniki said two men had been detained for trying to sell the statue for €40,000.
Police made the discovery after an undercover officer posed as a buyer and began negotiations with the two suspects.
The two individuals, both aged 56, were arrested on Friday while in possession of the "extremely rare" statue, police said in a statement.
A third man from Pella was also detained after he allegedly admitted to finding the statue on his farm and giving it to the two men to sell.
The marble work -- which pictures three conjoined figures of Hecate -- measures 33 centimetres high and 16 centimetres wide and weighs 10 kilograms.
Police have added that the piece holds "great archaeological value."
In ancient Greece, Hecate was venerated as a goddess of the underworld, capable of both good and evil. She was associated with magic, witchcraft, the moon, and creatures of the night such as ghosts.
The three arrested men have been charged with belonging to a criminal group and violating Greek laws on the protection of antiquities and cultural heritage.
Police have also seized a motorcycle belonging to one of the men, which was used to transport the statue to Thessaloniki.
The men will appear before a magistrate on Tuesday and face a maximum sentence of 12 months in prison and a €500 fine if convicted.