BACKGROUND Few studies have assessed the sensitization of mycotic allergens and Aspergillus fumigatus molecular allergens. This study aimed to investigate the relationships of A fumigatus components and mycotic allergens in allergic bronchopulmonary aspergillosis (ABPA) patients and A fumigatus (Af)-sensitized asthma patients. METHODS Serum sIgE levels of Penicillium chrysogenum, Cladosporium herbarum, Mucor racemosus, Candida albicans, Alternaria alternata, Helminthosporium halodes, and A fumigatus allergen components (Asp f 1, Asp f 2, Asp f 3, Asp f 4, and Asp f 6) were measured via the ImmunoCAP assay in 18 ABPA and 54 Af-sensitized asthma patients in Guangzhou city, China. RESULTS 94.44% of ABPA patients and 87.04% of Af-sensitized asthma patients were co-sensitized to at least one other fungal allergen. The positive rates of Asp f 1 (88.89% vs 59.26%, P < .05), Asp f 2 (66.67% vs 33.33%, P < .05), Asp f 4 (61.11% vs 33.33%, P < .05), and Asp f 6 (66.67% vs 14.81%, P < .001) in ABPA patients were higher than those in Af-sensitized asthma patients. IgE levels of Asp f 1 (P < .05), Asp f 4 (P < .05), and Asp f 6 (P < .001) were higher in ABPA patients than in Af-sensitized asthma patients. Optimal scale analysis showed that ABPA was more relevant to Af components (Cronbach's alpha = 90.7%). CONCLUSIONS The A fumigatus components and their relationships with various mycotic allergens were different in ABPA and Af-sensitized asthma patients. This finding may help local doctors in the diagnosis and immunotherapy of fungal allergies.