Treatment of active chronic viral hepatitis type C with interferon alpha has proved effective and therefore its use is being extended to a large number of patients. Common side effects include respiratory manifestations. One side effect attributable to the immunomodulatory effect of interferon is the possible triggering or exacerbation of systemic or cutaneous sarcoidosis. We report a new case and offer an exhaustive review of the literature. A 49-year-old man with type C chronic, active hepatitis developed new respiratory symptoms and pulmonary infiltrates with hilar and mediastinal adenopathy after 4 months of treatment with pegylated interferon and ribavirin. The transbronchial biopsy showed multiple sarcoid granulomas. When the patient was diagnosed, he had already taken the total dose of interferon and no specific treatment was started. His hepatitis did not respond to therapy and his viral load and transaminase levels remained high.