The Lithuanian Central Electoral Commission decided unanimously on Monday that the MP seat should go to Valiukevičiūtė, who served three terms as a lawmaker between 2004 and 2016.
She will be sworn in after the parliament's spring session opens on March 10.
Pūkas faced impeachment over sexual harassment allegations after the Constitutional Court ruled that he had breached the oath and violated the Constitution. He is suspected of sexually harassing several young women working as his assistants or applying for the job.
Prosecutors have brought formal suspicions of sexual harassment and violation of the rules for keeping firearms against the man.