At the outbreak of World War II, she was in eastern Poland but fled to Warsaw as soon as she could.
In July 1942, when the deportations from Warsaw were proceeding at an intensive pace, she helped found the ZOB. She became a member of the Jewish National Committee and the Coordinating Committee — the political arm of the ZOB — and the coordinating committee between the ZOB and the Jewish Socialist Bund. Lubetkin fought in the short January 1943 uprising in the Warsaw ghetto and again in the revolt that broke out on April 19, 1943. On May 10 she escaped by way of the sewers and remained in hiding until the Red Army took Warsaw, only emerging to take part in the Polish Warsaw uprising.
After the war she became active in survivor circles and the Beriha, an organization devoted to bringing Jews from Europe to Palestine. She reached Palestine herself in 1949 and helped found the Ghetto Fighters’ Kibbutz and its museum.
She married another former underground leader, Yitzhak Zuckerman.