Inspection of nails suggest an underlying systemic disease. Clubbing nail is mainly associated with pulmonary, neoplastic, and gastrointestinal diseases. It is characterized by thickening of the soft tissue beneath the proximal nail plate. It can be diagnosed with positive Lovibond angle and Schamroth’s sign. Lovibond angle is the angle between the proximal nail fold and the nail, which is considered pathologic when exceeding 180°. Schamroth’s sign is disappearance of the diamond shape which is normally made when the dorsal surfaces of two nails are attached. When it is observed, more exams are needed, based on associated symptoms with screening of malignancy. Especially, chest radiography should be performed to exclude pulmonary disease which is the most common cause of clubbing nail. A 79-year-old man presented with 1-year history of thickening on both nails. He was diagnosed as onychomycosis and treated with topical antifungal agents for 1 year at a local clinic without improvement. He had 25-pack-years of smoking history. On physical examination, enlargement of the ends of the fingers and toes and a downward sloping of the nails were observed with positive Lovibond angle and Schamroth’s sign. KOH smear for fungus was negative. He didn’t complain any other symptoms. Chest radiography showed interstitial lung disease on both lungs without active inflammation. We consulted to pulmonary department, but the patient lost to follow-up.