Severe asthma is a collection of disease entities with varying pathophysiological characteristics that result in symptoms of cough, wheeze and breathlessness, with frequent exacerbations. To address the problem of phenotypic difference and heterogeneity, the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) project was set up as a public-private partnership within the framework of the Innovative Medicines Initiative (IMI), engaging academia, the pharmaceutical industry and patient groups. The goal of this investigation was to identify proteomic fingerprints in induced sputum that characterize patients with severe asthma and to determine whether subgroups of severe asthmatics can be identified. Furthermore, we were interested in elucidating the biological pathways that showed differences between subgroups. This dataset is a description of the normal sputum proteome.