Upon her return to Warsaw, Altman found that the Jews were unwilling to accept that they were about to be exterminated, even after reports arrived of a death camp at Chełmno.
In early 1942, she collaborated with other leftist groups to establish a self-defense organization, but their efforts came to nothing because they were unable to secure any arms.
In July, during the Grossaktion Warsaw and after the establishment of the Jewish Combat Organization (ŻOB), Altman, due to her Aryan appearance and Polish language skills, was appointed a liaison with the Home Army and Armia Ludowa.
Although these Polish resistance organizations refused to offer any substantial help, Altman helped smuggle some grenades and explosives.
Living on the Aryan side of the city, she also helped Jews escape from the ghetto and find places to hide.
In a letter to Adam Rand, then in Vienna, in April 1942, she wrote, "Jews are dying before my eyes and I am powerless to help.
Did you ever try to shatter a wall with your head?"

In September, the Grossaktion finally ceased, leaving less than 70,000 Jews in the Warsaw Ghetto, one-fifth the original population.
The leadership of Hashomer Hatzair was damaged by Gestapo arrests and an explosives cache of another smuggler was detected.
Altman was joined by Arie Wilner, another Hashomer Hatzair activist, in an attempt to convince the Polish resistance groups to arm them.
She also continued her visits to other ghettos, this time organizing armed resistance.
She was instrumental in setting up a chapter of the ŻOB in the Kraków Ghetto.
In October, the Home Army recognized the ŻOB and began to provide weapons, starting in December.
Upon her return to Warsaw, Altman found that the Jews were unwilling to accept that they were about to be exterminated, even after reports arrived of a death camp at Chełmno. In early 1942, she collaborated with other leftist groups to establish a self-defense organization, but their efforts came to nothing because they were unable to secure any arms. In July, during the Grossaktion Warsaw and after the establishment of the Jewish Combat Organization (ŻOB), Altman, due to her Aryan appearance and Polish language skills, was appointed a liaison with the Home Army and Armia Ludowa. Although these Polish resistance organizations refused to offer any substantial help, Altman helped smuggle some grenades and explosives. Living on the Aryan side of the city, she also helped Jews escape from the ghetto and find places to hide. In a letter to Adam Rand, then in Vienna, in April 1942, she wrote, "Jews are dying before my eyes and I am powerless to help. Did you ever try to shatter a wall with your head?"
In September, the Grossaktion finally ceased, leaving less than 70,000 Jews in the Warsaw Ghetto, one-fifth the original population. The leadership of Hashomer Hatzair was damaged by Gestapo arrests and an explosives cache of another smuggler was detected. Altman was joined by Arie Wilner, another Hashomer Hatzair activist, in an attempt to convince the Polish resistance groups to arm them. She also continued her visits to other ghettos, this time organizing armed resistance. She was instrumental in setting up a chapter of the ŻOB in the Kraków Ghetto. In October, the Home Army recognized the ŻOB and began to provide weapons, starting in December.
Tosia Altman