Despite the many honours that Meitner received in her lifetime, she did not receive the Nobel Prize while it was awarded to Otto Hahn for the discovery of nuclear fission. She was nominated 49 times for Physics and Chemistry Nobel Prizes but never won. On 15 November 1945, the Royal Swedish Academy of Sciences announced that Hahn had been awarded the 1944 Nobel Prize in Chemistry for "his discovery of the fission of heavy atomic nuclei". Meitner was the one who told Hahn and Strassman to test their radium in more detail, and it was she who told Hahn that it was possible for the nucleus of uranium to disintegrate. Without these contributions of Meitner, Hahn would not have found that the uranium nucleus can split in half.
In 1945 the Nobel Committee for Chemistry in Sweden that selected the Nobel Prize in Chemistry decided to award that prize solely to Hahn: Hahn only found out from a newspaper while interned in Farm Hall Cambridgeshire England. In the 1990s, the long-sealed records of the Nobel Committees proceedings became public, and the comprehensive biography of Meitner published in 1996 by Ruth Lewin Sime took advantage of this unsealing to reconsider Meitners exclusion. In a 1997 article in the American Physical Society journal Physics Today, Sime and her colleagues Elisabeth Crawford and Mark Walker wrote: 
The five-member physics committee included Manne Siegbahn, his former student Erik Hulthén, the professor of experimental physics at Uppsala University, and Axel Lindh, who eventually succeeded Hulthén. All three were part of the Siegbahn school of x-ray spectroscopy. The poor relationship between Siegbahn and Meitner was a factor here, as was the bias towards experimental rather than theoretical physics. In his report on the work of Meitner and Frisch, Hulthén relied on pre-war papers. He did not think that their work was groundbreaking, and argued that the prize for physics was given for experimental rather than theoretical work, which had not been the case for many years.
At the time Meitner herself wrote in a letter, "Surely Hahn fully deserved the Nobel Prize for chemistry. There is really no doubt about it. But I believe that Frisch and I contributed something not insignificant to the clarification of the process of uranium fission—how it originates and that it produces so much energy and that was something very remote to Hahn." Hahn's receipt of a Nobel Prize was long expected. Both he and Meitner had been nominated for both the chemistry and the physics prizes several times even before the discovery of nuclear fission. According to the Nobel Prize archive, she was nominated 19 times for Nobel Prize in Chemistry between 1924 and 1948, and 30 times for Nobel Prize in Physics between 1937 and 1967. Her nominators included Arthur Compton, Dirk Coster, Kasimir Fajans, James Franck, Otto Hahn, Oscar Klein, Niels Bohr, Max Planck and Max Born. Despite not having been awarded the Nobel Prize, Meitner was invited to attend the Lindau Nobel Laureate Meeting in 1962.
Max Perutz, the 1962 Nobel prizewinner in chemistry, reached a similar conclusion: "Having been locked up in the Nobel Committees files these fifty years, the documents leading to this unjust award now reveal that the protracted deliberations by the Nobel jury were hampered by lack of appreciation both of the joint work that had preceded the discovery and of Meitners written and verbal contributions after her flight from Berlin."