Over the two-day summit, thousand took to the streets in protest. By September 25, 2009, police had arrested a total of 66 protesters. The ACLU criticized police for using pepper spray, throwing cans of smoke and using batons on some of the protesters. The legal director of ACLU Pennsylvania said, "In a week when we need freedom of speech more than ever, free speech died in Pittsburgh this week."http://www.google.com/hostednews/ap/article/ALeqM5jz5PoD9qb-An3UTF1pQjWpJgALBwD9AUJCRO1http://www.nytimes.com/2009/09/26/world/26pittsburgh.html

On April 1, 2009, protesters clashed with police in London and a group smashed windows at the Royal Bank of Scotland's building in the financial district. Some demonstrators vandalized the side of the building by spray painting the word "Thieves." Others entered the building and threw large office equipment onto the street. Several protesters were arrested. The protests continued as the summit began on April 2, 2009.WashingtonPost.com: G-20 Protesters Jam Downtown London, Target Banks (April 1, 2009)