There are many studies that examine the psychosocial adjustment of survivors of bone marrow transplantation (BMT). On the other hand, there are relatively few studies that examine the psychosocial adjustment of patients prior to BMT, and even fewer that focus on the psychosocial adjustment of the patient's caregiver. The purpose of the present study was to assess performance status and psychosocial adjustment to illness, mood and stress response of patients and caregivers prior to admission for allogeneic BMT. Forty patients and their 39 caregivers were assessed using standardized measures. One-fourth of the patients reported clinical levels of psychosocial maladjustment on the Psychosocial Adjustment to Illness Scale and had greater adjustment problems than BMT survivors. Approximately one-third (35%) and one-quarter (23%) of the patients reported significant symptoms of intrusive and avoidance stress responses, respectively on the Impact of Events Scale. Caregivers reported more impairments in family relationships than patients, but overall reported similar distress to that of patients. Information about the pre-BMT process appears to be critical to understanding the psychosocial impact that BMT can have on patients and their caregivers.