Roman Bezsmertnyy told a news conference in Kyiv that he is stepping down to concentrate on preparing for parliamentary elections next March.
Bezsmertnyy is head of the election campaign of the pro-presidential Our Ukraine party.
Campaigning for the polls officially kicks off on 26 November .
RFE/RL Belarus, Ukraine, And Moldova Report
SUBSCRIBE For weekly news and analysis on Belarus, Ukraine, and Moldova by e-mail, subscribe to "RFE/RL Belarus, Ukraine, And Moldova Report."