The purpose of the study was to analyze clinical and/or autopsy findings at the time of death among adults with sickle cell disease (SCD) at Howard University in Washington, DC over a 25-year period. A single physician recorded circumstances of death among 141 adult SCD patients he treated and knew well from 1976 to 2001. These findings were determined by autopsy report and/or clinical assessment. In a subset of 31 patients, autopsy records were reviewed for reports of iron deposition in liver and heart and of organ pathology. One hundred and fourteen (80.9%) of the patients had SS phenotype and 66 (46.8%) were female. The mean ± SD age at death was 36 ± 11 years. Leading circumstances of death included pulmonary hypertension (PHT) (26.2%), sudden death (23.4%), renal failure (22.6%), infection (18.4%), thromboembolism (14.9%), cardiac diagnoses (12.0%), cirrhosis (11.3%), pneumonia or acute chest syndrome (9.9%), bleeding (7.8%), and iron overload (7.0%). When circumstances of deaths that occurred after 1991 (n = 69) were compared to those that occurred in 1991 or earlier (n = 72), PHT (36.2% vs. 16.6%; P < 0.01) was significantly more common in 1992 or later. Significant associations were found between PHT and thromboembolism and between cirrhosis and iron overload. In this proportional mortality study of adults with SCD, PHT was the leading finding at the time of death. Thromboembolism was associated with PHT, and iron overload was associated with cirrhosis. Am. J. Hematol. 81:858-863, 2006. V V C 2006 Wiley-Liss, Inc.