Medvedko, who held the post of deputy prosecutor-general, was nominated by President Viktor Yushchenko.
Medvedko replaces Svyatoslav Piskun, whom the Ukrainian president sacked last month after accusing him of dragging out important investigations.
Piskun is appealing in court the decision to dismiss him.
Medvedko was approved as Ukraine's new prosecutor-general by a total of 303 votes, well above the 226 votes needed for confirmation in parliament.
(Interfax/AFP/ITAR-TASS)