The Distress Thermometer (DT) is a one-item screening measure of psychological distress in cancer patients. This study examines the operating characteristics of the DT in patients about to undergo bone marrow transplant (BMT). Patients (N=491) completed the DT, the Center for Epidemiological Studies-Depression Scale (CES-D), the State-Trait Anxiety Inventory-State Version (STAI-S), the ECOG Performance Status Scale, and the Patient Problem List. DT scores were related to higher depression, higher anxiety, and poorer performance status. Receiver operating characteristic (ROC) curve analyses of DT scores yielded area under the curve estimates of 0.75 when compared to the CES-D cutoff score of 16, suggesting the DT has acceptable overall accuracy. The DT cutoff score of 4 had the greatest sensitivity and specificity when compared to the CES-D cutoff score. Patients above this cutoff score reported worse ECOG scores and more practical, family, emotional, and physical problems (all p's⩽0.05) than those below the cutoff. The findings suggest the DT is a useful tool for screening for distress in BMT patients. The optimal DT cutoff score of 4 found here was identical to that found in another study using different criteria. This cutoff score also identified patients with problems likely to reflect psychological distress. Copyright © 2005 John Wiley & Sons, Ltd.