Background and study aim: Interstitial lung disease (ILD) includes a variety group of about 200 conditions that insult the lung parenchyma with different patterns of inflammation and fibrosis. Hepatitis C virus (HCV)is Flavivirus with diverse hepatic and extrahepatic diseases. Its direct and indirect pathogenic association with many pulmonary manifestations-including interstitial lung disease-has been suggested yet needs more elucidation. Patients and Methods: A case control study was conducted with a total of 50 chronic hepatic patients. They were equally divided into two groups, HCV positive group (group 1= 25 patients) and HCV negative group (group 2= 25 patients). Group 1 was subdivided into two subgroups, without-idiopathic interstitial pneumonias patients (without IIPs subgroup A= 13 patients) and with idiopathic interstitial pneumonias patients (IIPs subgroup B = 12 patients). Both groups were subjected to thorough history taking, clinical examination, and routine investigations. The diagnosis of HCV was confirmed by viral markers including HCV antibodies and PCR. Other chronic hepatic liver diseases were confirmed by abdominal ultrasound and ultrasound- guided liver biopsy. Arterial blood gases, auto antibodies, Computerized pulmonary function tests and radiological studies including plain X ray chest and heart and HRCT scanning were also done. All patients with idiopathic pulmonary fibrosis (IPF) had fulfilled the ATS/ ERS diagnostic guidelines. Both groups were matched according to age, sex and body mass index. Results: The HCV positive group was found to have a significantly higher frequency of ILD than the HCV negative group with also more restrictive pattern hypoxemia and higher scores of IPF (by computed tomography). Conclusion: ILD is more frequent in patients with chronic HCV infection with higher grades of fibrosis and hypoxemia. HCV infection may be predisposing factor for IPF.