The number of long-term survivors after allogeneic bone marrow transplantation (BMT) has been increasing over the past years, and quality of life (QOL) has become an important end-point. We studied 244 patients undergoing an allogeneic BMT to identify factors and events influencing psychosocial outcome. Patients enrolled received the Psychosocial Adjustment to Illness Scale (PAIS) questionnaire assessing psychological and social adjustment to chronic illness or its sequelae. Eighty-two per cent of patients had a haematological disease. The median age was 28 years at BMT, and the median follow-up was 61 months. The median overall PAIS score for all patients was 56 (range 22-76): 25% (n = 61) of patients were considered to have a good QOL (</= 25 percentile score); 44% (n = 108) of patients had an intermediate QOL (26-75 percentile score) and 31% (n = 75) had a poor QOL (> 75 percentile score). Factors associated with a poor QOL in multivariate analysis were: patients' age at BMT (> 25 years, P < 0.01); presence of long-term sequelae (P < 0.01); chronic graft-versus-host disease (GVHD) (P < 0.05); and a short interval from BMT (< 5 years; P < 0.05). The QOL improved with time: 12% of patients reported a good QOL within 5 years compared with 38% after this time point and, conversely, 38% reported a poor QOL within 5 years compared with 24% after this time point (P < 0. 0001). Older patients had significantly poorer QOL compared with younger patients (< or = 25 years; P = 0.01). Females had significantly poorer scores when compared with males in the sexual (P < 0.0001) and psychological domains (P = 0.001). The data suggest that (i) one-third of patients undergoing allogeneic BMT report a poor QOL; (ii) factors associated with poor QOL are older age, presence of long-term sequelae, chronic GVHD and short follow-up; (iii) QOL is superior in long-term survivors; and (iv) BMT affects different aspects of life in males and females. A longitudinal study is ongoing to prove the effect of time on quality of life.