Cohler, who was one of the first members of staff at Facebook, is not severing all ties with his former employer as he will become a formal advisor to Mark Zuckerberg, Facebook's founder.
Zuckerberg said: "[Cohler] has been an important contributor to Facebook's growth and success and we are pleased he will continue working in a formal role as a special advisor to me and the Facebook management team."
Cohler's departure comes six weeks after Facebook's chief technology officer Adam D'Angelo parted ways with the social networking site.
Separately, has set up a Chinese version of its site.
Users accessing Facebook from mainland China are now redirected to , which features a simplified version of Chinese used on mainland China.
Facebook has also created a version in traditional Chinese -- the language used in Hong Kong and Taiwan.
The Chinese versions follow the launch of Spanish, German and French versions earlier this year.
News Corporation's already has more than 20 country-specific sites and has versions in Spanish, French, German and Italian, as well as in Chinese, which was launched in April 2007.