Bartkus will be sworn in by President Dalia Grybauskaitė after the parliament on Tuesday approved his appointment as the next head of the anti-corruption agency.
He replaces Saulius Urbanavičius, whose five-year term in office ended on Thursday.
Bartkus has been working at STT since 1999. He has held the post of first deputy director at the anti-corruption agency since April 2013.