The two families – those of Waleria and Marcin Swietlik and Helena and Stanislaw Podrzycki - were posthumously honoured because they risked their own lives to save two Jewish girls when Poland was under German occupation during World War II.
The ceremony was held as part of commemorations of the 72nd anniversary of the liquidation of the Lodz Ghetto, the second-largest ghetto in all of German-occupied Europe after the Warsaw Ghetto.
The Righteous Among the Nations medals are awarded by the Jerusalem-based Yad Vashem Institute to individuals and families who risked their own lives and the lives of their loved ones to rescue Jews from the Holocaust.
A total of 26,120 people have received the medal worldwide, with Poles representing the largest group among them, at 6,620. (PAP)