Bone marrow transplantation (BMT) is becoming a widely used therapeutic modality in the field of cancer care. Offering long-term disease-free survival in more than half of some patients with previously fatal diseases, this therapy has challenged clinicians to reevaluate critical care management strategies for such patients. Critical Illness occurs in approximately enc third of allogeneic transplants, necessitating that critical cars nurses be familiar with this therapy and its reported complications. Critical care nurses are an Integral part of producing the reported cure and remission rates, despite significant complications. In this article, the authors outline the common critical care problems of this patient population. The chronologic format enables the practitioner to correlate and differentiate key characteristics of potential complications. A case study, with clinical symptoms representing several potential etiologies, demonstrates the application of these concepts. Through the use of nursing knowledge of the unique needs of these patients, there is the potential to continue to improve patient outcomes.