He will wear the No. 29 shirt for Zenit. The loan is until the end of the season, and journalists have speculated that a permanent deal may well follow in the summer.
Arshavin has had a largely underwhelming season for Arsenal with only eight starts in the Premier League, and yielding only three assists and one goal.
Still, with Arsenal's squad already stretched thin, and the likes of Gervinho and Theo Walcott often inconsistent, the move comes as a surprise to many Arsenal fans.
After a dazzling start, it seems that Arshavin is destined to be remembered as a player who never quite came through on his early promise in England.