The prevalence of allergic bronchopulmonary aspergillosis (ABPA) in chronic asthma has been reported in various studies. However, no study has systematically evaluated the occurrence of Aspergillus hypersensitivity (AH) and ABPA in acute severe asthma (ASA). The aim of this study was to investigate the occurrence of AH and ABPA in patients with ASA. All patients with ASA admitted to the respiratory intensive care unit (ICU) of this institute underwent a prospective evaluation for ABPA using Aspergillus skin test (AST) as a screening tool. Patients with positive AST were labelled as AH and were further investigated for ABPA. Patients with ASA were compared with historical control group of 755 outpatient bronchial asthma patients previously reported. Of the 357 ICU admissions, 57 (43 females, 14 males; mean age 43.5 years) patients were admitted with a diagnosis of ASA. The occurrence of AH was 50.9% [95% confidence interval (CI) 38.3-63.4; 29/57 patients] whereas the prevalence of ABPA was 38.6% (95% CI 27.1-51.6; 22/57 patients) in patients with ASA. The occurrence of AH and ABPA was significantly higher in the ASA group compared with the outpatient bronchial asthma group (38.5% and 20.5%, respectively). The prevalence of serological ABPA (ABPA without central bronchiectasis) was also higher in the ASA group compared with the outpatient bronchial asthma group (45.4% vs. 23.9%). The occurrence of AH and ABPA is very high in patients with acute asthma admitted to a respiratory ICU. Furthermore, the occurrence of high percentage of serological ABPA calls for the use of AST as a routine screening tool for ABPA in all patients with acute asthma at discharge.