Idiopathic pulmonary fibrosis is a chronic progressive interstitial lung disease of unknown etiology, characterized by inflammation and fibrosis of the lung parenchyma. No specific pathognomonic clinical or pathologic findings are associated with IPF, and diagnosis depends on exclusion of other causes of interstitial lung disease. Clinical features consist of progressive dyspnea upon exertion, interstitial infiltrates on chest radiographs, and a restrictive ventilatory defect found on pulmonary function test results. The course of IPF is variable and unpredictable. IPF affects more males than females. IPF affects elderly persons, with an average age of onset of approximately 60 years. Open lung biopsy and video-assisted thoracoscopic lung biopsy are the criterion standards for the diagnosis of IPF. Treatment with systemic corticosteroids, other immunosuppressant, or both may benefit patients with lung histopathology patterns of high cellular inflammation and less fibrosis.