The Ukrainian parliament has approved the resignation of Prosecutor-General Viktor Shokin.
He was seen by Ukraine's Western backers as an obstacle to tackling corruption.
The motion to approve his resignation passed on March 29 with 289 votes, comfortably over the 226 required.
An hour earlier, Shokin had fired his deputy, Davit Sakvarelidze, one of several foreign-born experts brought in to assist Ukraine with its Western-backed reform drive. Sakvarelidze had accused Shokin of maintaining ties with corrupt officials and lawmakers.
Several hundred people rallied outside the Ukrainian parliament on March 28, calling for Shokin's resignation.
The United States has repeatedly called for top-to-bottom reform of the Prosecutor-General's Office, which antigraft campaigners have said plays a key role in protecting vested interests and allowing corrupt practices to flourish.
Shokin had tendered his resignation on February 16 after President Petro Poroshenko asked him and Prime Minister Arseniy Yatsenyuk to step down.
Parliament is expected to debate a motion to fire Yatsenyuk later on March 29.
Parliamentary speaker Volodymyr Hroysman appears to have the backing in parliament to lead a new government.
Based on reporting by Reuters and Interfax