Aspergillus spp. often colonise the respiratory tract of critically ill patients in intensive care units and subsequently cause invasive disease. The risk of developing invasive disease is more in immunocompromised patients. Here we report a case of fatal invasive pulmonary aspergillosis caused by Aspergillus versicolor in a post-operative patient on mechanical ventilation, who did not respond to intravenous itraconazole. We then discuss the challenges involved in the accurate diagnosis of this condition and appropriate management.