Parliament has also passed a law that will give "special status" to the separatist eastern regions, including a degree of self-governance for a three-year period, parliamentary deputies who attended Tuesday's closed session told Reuters.
A second law that was passed would grant an amnesty to separatists who were involved in recent fighting with government forces, the deputies reportedly said.
The development comes as a ceasefire agreement with pro-Russian separatists in eastern Ukraine, signed earlier this month in the Belarusian capital Minsk, has been riddled with violations from the start.
MPs in the Ukrainian and European parliaments ratified the 1,200-page political and economic association agreement during a live video metting.
The two sides decided to bow to Russian pressure and delay applying the free-trade rules that pulled Ukraine out of a rival union being built by the Kremlin. Therefore, the key element of the agreement has been postponed until 2016.
Russia has threatened to block Ukrainian goods to Russia if Kiev lowers trade barriers with Europe.
The EU has said it would allow Ukraine to maintain its current tariffs until early 2016, but it would still have to undertake major economic and political reform required by the agreement.
The rejection of the same EU deal by Kremlin-backed President Viktor Yanukovych in November led to the bloody chain of events that led to his February overthrow and Russia's subsequent seizure of Ukraine's Crimea peninsula.