BACKGROUND: Quality of life is an important Healthcare outcome to study. Quality of life after heart transplantation has not been compared with indicators of severity of illness before heart transplantation. OBJECTIVE: To compare differences in quality of life 6 months after heart transplantation with two preoperative indicators of severity of illness: New York Heart Association classification and United Network for Organ Sharing status. METHODS: Data were collected from a nonrandom sample of 219 adult patients who had received a heart transplant 6 months earlier. Patients were divided into groups on the basis of their New York Heart Association classification and United Network for Organ Sharing status immediately before transplantation. Instruments used were the Heart Transplant Symptom Checklist, Heart Transplant Stressor Scale, Rating Question Form, Quality of Life Index, Sickness Impact Profile, and Jalowiec Coping Scale. Data were analyzed with descriptive statistics, chi-square tests, and independent t tests. RESULTS: Quality of life 6 months after receiving a heart transplant varied with severity of illness before transplantation. These differences in quality of life were in the following domains: physical and occupational function, psychological state, and social interaction. Six months after receiving a heart transplant, patients who were more severely ill before transplantation were less satisfied with their lives, perceived that they were not doing as well, experienced more family-related stress, and used more negative coping strategies than did patients who were less severely ill preoperatively. CONCLUSIONS: These findings indicate the need for further study of quality of life in the transplant recipients who are the most critically ill in intensive care settings before surgery, to develop interventions to improve recipients' quality of life, and to evaluate effectiveness of those interventions longitudinally.