When the Germans invaded Warsaw in 1939, Irena began helping Jews with food, shelter, and false documents. Her position as an administrator at the Warsaw Social Work Department allowed her to develop a network of 24 helpers who rescued children and found them hiding places in Polish homes, convents, and orphanages.
In her role as a social worker, she was permitted to enter the Warsaw Ghetto. For a three month period in the summer of 1942, she worked to smuggle out children, including infants. When the underground group Zegota organized that fall, Irena headed the children’s division. She carefully documented the names of the hidden children in jars and buried them, so the children could be reunited with their true families after the war.
They saved the lives of 2,500 children from the Holocaust.

On October 20, 1943, the Gestapo captured Irena and placed her in Pawiak Prison, where she was questioned and tortured. Her legs and feet were broken and she was sentenced to death. Zegota bribed the executioner to help her escape, and she remained in hiding for the remaining years of the war. After World War II ended, Irena dug up the jars and began the job of trying to find a living parent for the hidden children.
In 1965, Yad Vashem honored Irena as Righteous Among the Nations.
Irena received the 2003 Jan Karski award for Valor and Compassion and in 2007, she received a nomination for the 2007 Nobel Peace Prize.
Irena Sendler passed away on May 12, 2008, in Warsaw, Poland.