Thames Valley Police today confirmed the man from London was arrested on suspicion of handling stolen goods.
The loo has never been found after the September raid - with fears it could be melted down by thieves.
Police previously revealed the thieves had used at least two cars to snatch the toilet.
It was created by Italian artist Maurizio Cattelan and proved popular when it went on display at the Guggenheim museum in New York in 2016.
The masterpiece was once offered to President Donald Trump who turned it down.
The Duke of Marlborough’s half-brother and founder of the Blenheim Art Foundation Edward Spencer-Churchill previously told the Times: "Despite being born with a silver spoon in my mouth I have never had a s*** on a golden toilet, so I look forward to it."
He also explained it "wouldn't be the easiest thing to nick", adding: "Firstly, it’s plumbed in and secondly, a potential thief will have no idea who last used the toilet or what they ate.
"So no, I don’t plan to be guarding it."
COPS INVESTIGATECops said: "A 35-year-old man from London was arrested this morning on suspicion of handling stolen goods and remains in police custody.
"The arrest is in connection with an incident on September 14 this year, when a golden toilet was stolen from Blenheim Palace."
Previously, a 66-year-old man from Evesham, Worcs., was arrested on suspicion of burglary.
A 35-year-old man from Cheltenham, Gloucs., was also arrested on suspicion of conspiracy to burgle.
A 35-year-old man, a 34-year-old man and a 36-year-old woman, all from Oxford, were arrested on suspicion of conspiring to commit a burglary other than a dwelling.