Data on the radiological features of invasive pulmonary aspergillosis (IPA) in early stages is scanty. Detection of Aspergillus (ASP) species in broncho-alveolar (BAL) fluid by polymerase chain reaction (PCR) enables early diagnosis of IPA. This study describes the radiological features of early stages of IPA. Chest computerized tomography (CT) films of 22 consecutive immune-compromised patients with IPA diagnosed with the aid of ASP PCR testing from BAL fluid were characterized and compared to that of 18 similar patients diagnosed with traditional bacteriological methods and to data from the literature. It was found that patients diagnosed with the aid of ASP PCR testing tended to have focal disease as manifested by more 11-30mm nodules with halo (68% vs. 33%,p= 0.04), more focal ground glass (single area 32% vs. 6%,p= 0.05, patchy 32% vs. 0%,p= 0.01) and less diffuse ground glass (0% vs. 22%,p= 0.03), less cavitations (5% vs. 28%,p= 0.05) and less consolidations (segmental 14% vs. 50%,p= 0.02 and diffuse 14% vs. 67%,p= 0.001). It was concluded that the radiological appearance of early IPA diagnosed with the aid of PCR testing included mainly discrete small nodules with halo and focal ground glass, representing the early stage of the disease.