Donetsk People's Republic (DPR) officials told journalists earlier the conflicting parties had agreed for an equal exchange, with each party promising to hand over 73 captives.
Despite the "balance disparity," the militia said they would still honor the conditions of the agreement as announced on Saturday.
"We are going to hand over 73 people," a member of the DPR self-defense forces told RIA Novosti.
The 69 former hostages who had been held by Ukraine's security forces looked worn out as they walked over to be greeted by the Donetsk independence supporters. The freed prisoners, among them a priest from the Orthodox Christian Church, confessed they had been subject to violence while in Kiev captivity.
The exchange took place in eastern Ukraine, about 30 kilometers to the north of the region's capital city Donetsk.
The swap follows a groundbreaking ceasefire agreement in Belarus' capital Minsk on September 5 where Ukraine, Russia and the Organization for Security and Cooperation in Europe (OSCE) agreed to exchange all captives held by Kiev and militias in the breakaway eastern regions, in what they described as an "all-for-all" prisoner exchange.
Negotiators were building on Ukrainian President Petro Poroshenko's peace plan for resolving the conflict in eastern Ukraine, as well as on Russian President Vladimir Putin's proposals.