The 25-year-old joins on a long term contract for an undisclosed fee. The highly rated Barcelona winger made a total of 88 appearances, scoring 39 goals during his three seasons with the Catalan side.
Sanchez said: “I’m so happy to be joining Arsenal, a club which has a great manager, a fantastic squad of players, huge support around the world and a great stadium in London. I’m looking forward to meeting my new team-mates and to be playing for Arsenal in the Premier League and Champions League. I will give my best to Arsenal and want to make all the supporters happy.”
Liverpool were thought to be interested in Sanchez and wanted to him include him in a part exchange deal for Luis Suarez, but the Chilean wanted to join Arsenal only. The Gunners are also closing in on signing Mathieu Debuchy from Newcastle United.