Bone marrow transplantation (BMT) is an invasive and taxing treatment for certain cancers. This study investigated the psychological constructs of optimism and dispositional coping and their relative predictive role for situational coping. Participants were 85 cancer patients enrolled in a randomized clinical trial of T-cell depletion for prevention of graft-versus-host disease (GVHD) who completed baseline and 1-year interviews. Results of simultaneous regression analyses showed that optimism did not predict situational instrumental or palliative coping strategies but was negatively predictive of situational avoidant coping. Each of the three situational coping strategies was most strongly predicted by the corresponding dispositional coping strategy.