Invasive aspergillosis remains an important cause of morbidity and mortality in patients with prolonged and severe immune suppression such as following haematopoietic stem-cell transplantation. Consensus definitions, which allow categorisation of patients based on diagnostic criteria, are an important improvement in uniform registration of invasive mycoses in clinical trials. Prospective monitoring of high-risk patients for the circulating aspergillus cell-wall component galactomannan, results in earlier diagnosis in two-thirds of patients when compared with conventional diagnostic methods. High-resolution CT (HRCT) enables the lesions characteristic of invasive mycoses to be detected earlier and better than by chest radiograph. In addition, invasive mycoses cause characteristic lesions on the HRCT scan including the halo-sign and the air-crescent sign. The pre-emptive management strategy which combines monitoring of patients for surrogate markers with a HRCT scan appears to be a promising approach to the early identification and treatment of patients with invasive aspergillosis.