In the last 40 years, allogeneic bone marrow transplantation (BMT) has progressed from the laboratory and animal models to benefit humans with life-threatening illnesses. Therapeutic outcomes have continued to improve, as has long-term survival. The advent of this advanced technology in medicine has produced survivors of serious illness, patients who otherwise would have died years earlier. The challenge for nursing in this rapidly growing field is to provide comprehensive, quality care to a sick population. The article attempts to develop Watson's concept of human care through the role of the nurse practitioner. Allogeneic BMT is explained, and Watson's theory and its application to BMT are explored.