Interstitial pulmonary fibrosis is rare clinical entity related to welding usually associated with long term and heavy exposure to welding fumes. A 56-year-old asymptomatic male patient was referred to our clinic due to abnormal chest X-ray findings that was requested for regular controls. He has been working as a welder both indoor and outdoor settings for the last 25 years. The radiological findings were compatible with usual interstitial pneumonia on computed tomography of thorax. Pulmonary function tests, exercise capacity and laboratory results were within normal limits. Collagen tissue markers were negative. In order to confirm the relation of welding with pulmonary fibrosis, bronchoalveolar lavage was performed and stained with Prussian blue. The demonstration of hemosiderin-laden macrophages (25%) confirmed this association and allowed differential diagnosis. Besides it helped the patient decide to leave his job.