Introduction Clinical symptoms of Diffuse Parenchymal Lung Disease (DPLD) are dyspnoea and dry cough. On auscultation, crackles can be detected at an early stage. The aim of this study was to analyse whether the extent of abnormal breath sounds (crackles, wheezes and coughs) provides an indication of the disease severity and aetiology. Methodology In 25 patients with DPLD, an in- hospital overnight recording of physiological and abnormal breath sounds was performed with the LEOSound® monitor. The severity of pulmonary fibrosis was assessed by body plethysmography and GAP score. The perceived breathlessness was assessed by King's Brief Interstitial Lung Disease (K-Bild) questionnaire. Results In 16 out of 25 patients, all data were completed in good quality for analysis. Five patients were women (31.3%). The patients’ mean age was 65.8 ± 7.3 years, the mean BMI 28.0 ± 2.4 kg/m2. One patient met GAP I criteria, eight patients GAP II and seven patients met GAP III criteria. The findings of eight patients with idiopathic pulmonary fibrosis (IPF) were compared with those of eight patients with secondary interstitial lung disease (ILD). Both, the number of inspiratory crackles and coughs showed significant correlations with the severity of dyspnoea and ILD-pattern. Wheezing occurred in 15 patients, with a median of 25.7 wheezes/h. Discussion Overnight long-term auscultation in patients with pulmonary fibrosis proved feasible in our study. Regardless of the aetiology and disease severity, crackles were detected in the recordings of all fibrosis patients, but not cough. Wheezing occurred in 15 out of 16 patients, the significance of which for clinical practice must still remain unclear.