Idiopathic pulmonary fibrosis (IPF) is a severe progressive fibrotic disease of the lung. Its etiology is not yet completely clear. The affected population is exclusively older than 40 years with maximum incidence in the age categories of 60 to 70 years. Its worldwide prevalence varies from 2 to 29/100 000 people (in the Czech Republic 5-6/100 000). Annual incidence is constantly rising, mainly thanks to the ever-improving diagnostic possibilities. Untreated IPF disease causes rapid structural and functional devastation of the lungs with development of respiratory insufficiency and death of the patient within 2 to 3 years after diagnosis, prognosis with IPF is therefore fully (without any exaggeration) comparable to untreated bronchogenic carcinoma. In recent years, the prognosis and quality of life of patients have significantly improved thanks to available specific antifibrotic treatment, which can substantially slow down the disease progression and thus prolong survival. However, a necessary condition for the timely treatment initiation is a quick and accurate diagnosis. The following case report describes a protracted journey to the correct diagnosis in a patient with atypical radiological findings, so that the definitive diagnosis was established only as a result of a surgical lung biopsy.