The vote in the lower house of Parliament was overwhelming with 445 delegates voting for the reunification treaty and only one opposing it, the government-supported news agency RIA Novosti reported.
President Vladimir Putin signed the treaty Tuesday, two days after a hastily called referendum in the Crimea in which almost 97 percent of those who voted supported secession from Ukraine.
Pavlo Shysholin, deputy head of the Ukrainian State Border Guard Service, said Thursday that troops are being moved from Crimea to the Ukrainian mainland, Interfax-Ukraine reported.
"As for the personnel who are serving on the territory of Crimea, I would say we have begun gradual redeploying to the territory of Ukraine," he told reporters in Kiev.
Shysholin said about 1,000 people have left Crimea for Ukraine, saying they were forced out. He said border guards are inspecting all cars, trucks and trains crossing the new border.