The mental status of 39 leukemia patients, who received bone marrow transplants (BMT), was studied during the period of isolation. Mental disorders (diagnosed according to DSM-IV criteria) occurred in 16 patients (41%) during the observation period. The most frequent diagnoses were adjustment disorders, with anxiety and/or depression. Logistic regression analysis suggested higher Tension-Anxiety score in the Profile of Mood States (POMS) prior to isolation (P = 0.011), donation of the bone marrow from unrelated subjects (P = 0.026) and in female patients (P = 0.033). The results are preliminary, but indicate a high frequency of mental disturbances and highlight the importance of psychiatric intervention in BMT patients. Bone Marrow Transplantation (2000) 25, 315-318.