The 30-year-old returns to his former club on the final day of the Russian transfer window after struggling for form under Arsene Wenger at the Emirates
The 30-year-old has struggled for form in the 27 appearances he has made this season and has returned to Zenit on the final day of the Russian transfer window.
Arshavin posted on his official website: "I've moved to "Zenit". On loan, will play under number 29."
With Gervinho returning from the Africa Cup of Nations earlier this month, Arshavin's chances of securing a regular first-team role ahead of Russia's Euro 2012 campaign this summer looked limited.
Arsenal confirmed the reason behind the midfielder's move to Zenit was so that he could "maximise his opportunities for regular first-team football ahead of Euro 2012 in June".
Arshavin joined Arsenal in February 2009 from Zenit for a reported £15 million fee.