Clegg was hit with the paint, a reference to his decision to form a coalition with the Conservatives, as he arrived at a party meeting in Glasgow, a newspaper reports.
Some one hit him in the face, but he was unhurt and carried on with the meeting.
Clegg laughed off the incident, saying: "I've got three kids under 10, I'm quite used to having paint on me."
Stuart Rodger, a 22-year-old politics student at the University of Glasgow, was arrested following the incident at Woodside Hall in the west of the city.
Friends said Rodger, who is a member of the protest group UK Uncut, had been a Liberal Democrat member for two years, but left the party last May after the Coalition was formed.
"He went along to show his disgust at the right-wing turn the Liberal Democrats have taken," a friend said.
One of the witnesses said that Clegg laughed it off the incident saying these things tend to happen sometimes in the job and it's no big deal. He took it in good humour.
"People rushed to his aid to wipe it off. There were still traces of the blue paint on his clothing," the witness added.
London: British Deputy Prime Minister Nick Clegg has been attacked with an egg filled with blue paint by a disillusioned Liberal Democrat.
First Published: Friday, August 26, 2011, 14:26