The remains were recovered from two former Polish villages, Wola Ostrowiecka and Ostrówki, in western Ukraine, during excavations carried out between July 13 and August 7.
More than 300 personal items were also found at the sites, Poland's Institute of National Remembrance (IPN) said on Friday.
Most were uncovered in a mass grave on what was once a farm in Wola Ostrowiecka, where 48 bodies were found – 24 of them children, many under the age of 12.
Investigators said the remains had been buried in multiple layers and in random positions, consistent with witness accounts that victims were killed in a barn before their bodies were thrown into nearby pits.
Skull injuries were found on most of the remains, along with religious items including crosses, rosaries and medallions bearing Polish inscriptions.
At a second site near a former school in Ostrówki, the remains of six people, including two children, were found buried face down.
Gunshot wounds were identified on the skulls and a thigh bone.
DNA samples have been taken in an effort to identify the victims.
Historians estimate that around 300 more people from the area have yet to be found.
The remains will be reburied on August 30, the 83rd anniversary of the massacre, at a cemetery in Ostrówki.
The Volhynia massacres were a series of ethnic killings carried out during World War II, primarily in 1943 and 1944, in which tens of thousands of Polish civilians were killed by the Ukrainian Insurgent Army (UPA) in areas that are now part of western Ukraine.
The former villages of Ostrówki and Wola Ostrowiecka, once part of Poland's eastern Volhynia, are now in Ukraine's Volyn region near the city of Kovel, after borders shifted following World War II.
The events remain one of the most sensitive issues in Polish-Ukrainian relations.
The Volhynia region, then part of Poland, was occupied by the Soviet Union in 1939 under the Molotov-Ribbentrop Pact before being seized by Nazi Germany in 1941.
(ał/gs)
Source: PAP