Ukrainian Parliament and the European Parliament has ratified the Association Agreement, which establishes a deep political association and free-trade area between Ukraine and the EU.
Ukrainian President Petro Poroshenko told lawmakers the ratification of the agreement was a "first step" toward membership of the European Union.
"Tell me, who will now dare to shut Ukraine's doors to Europe? Who will be against our future membership in the EU, toward which today we are taking our first but very decisive step?" he said.
Refusal to sign the Association Agreement by Ukraine’s ousted leader Viktor Yanukovich sparked months of protests known as Euromaidan and the rebellion by pro-Russian separatists in eastern Ukraine.
However, the EU and Ukraine agreed on September 12 to delay implementation of the free-trade pact until the end of 2015 in a concession to Russia, which has pushed Kyiv to join a Russian-led Eurasian customs union.