Adenovirus has emerged as an important pathogen in immunocompromised patients, in whom disseminated disease occurs frequently and is associated with a high mortality rate. In a retrospective review of 1,847 consecutive autopsies, we identified 84 cases where adenovirus infection was suspected clinically. Adenovirus infection was confirmed at autopsy in 8 (10%) of 84 cases; all were immunocompromised patients. Six (75%) of these cases had disseminated adenovirus infection that contributed to death. Pathologic findings attributed to adenovirus infection included pneumonia with or without intra-alveolar hemorrhage, hepatic necrosis, enterocolitis with or without mucosal hemorrhage, epicardial hemorrhage, and ulcerations of the larynx, trachea, and ileum. This work shows that severe and fatal adenovirus infections are not infrequent, particularly in the immunocompromised population. Both clinicians and pathologists must become aware of the pathogenicity of adenovirus in this patient population, including its potential for causing life-threatening hemorrhage.