As a result, the company is no longer in compliance with NASDAQ listing requirements, according to a disclosure statement that Zynga filed with the SEC on Friday.
Per NASDAQ requirements, the board of directors of a member company must have a majority of independent directors.
Zynga said its remaining board members are actively working to find replacements for Hoffman and Katzenberg. Zynga has until July 27 to file its new board of directors plan, and thus, become in compliance with NASDAQ rules.
An email to Reid Hoffman was not returned, and a representative for Katzenberg did not respond to a request for comment. A Nasdaq spokesperson declined to comment.
Earlier this month, Venture Beat reported three top executives at Zynga have left the company, including Words With Friends head Travis Boatman, head of acquisitions Terence Fung, and the former head of the company's Ville franchise Steve Chiang.
—By CNBC's Mark Berniker