We present two cases of aspergillus infection confirmed by blood culture and review 30 other cases of genuine aspergillus fungemia and 34 cases of aspergillus pseudofungemia. Multiple different media and blood culture systems were used to isolated Aspergillus. The median time to positive blood culture was 8.5 days (range, 1-27 days) in the genuine cases. Genuine aspergillus fungemia was observed more often after cardiac surgery (n = 11 [34%]) or during neutropenia (n = 9 [28%]) than in other settings. In a recent series of fungemia during neutropenia, 7.6% of all episodes were due to Aspergillus. Other patients at risk for aspergillus fungemia were similar to those at risk for invasive aspergillosis, including patients with AIDS. Seven (44%) of 19 patients who were treated survived. In the group of patients with aspergillus pseudofungemia, there were no deaths, and cultures of additional specimens from the same patient were not positive. Criteria that may be applied to ascertain whether the isolation of Aspergillus from blood cultures is clinically significant are put forward.