An 84‐year‐old man with a history of progressive interstitial pneumonia presented to our department with lung cancer (cT2aN0M0‐IB) in right S6. Moreover, computed tomography revealed progressive diffuse pulmonary ossification in the bilateral lower pulmonary lobes. S6 segmentectomy was performed via video‐assisted thoracoscopic surgery. It was difficult to divide the intersegmental plane using a stapler because of severe fibrosis and pulmonary ossification with bone marrow formation. Pulmonary ossification may be an important finding for surgical planning because of severe fibrosis or inflammation associated with severe lung condition. We suggest that the surgical indications and approaches for such cases should be reconsidered because pulmonary ossification can be associated with severe lung conditions.