Pegylated interferon and ribavirin is the treatment of choice in patients with chronic hepatitis C infection. The most common side effects of interferon therapy are flu-like symptoms and psychiatric disorders. Pneumonitis is a less frequent complication associated with non-negligible mortality. We herein report a case of interferon associated pneumonitis in a patient with non-severe clinical symptoms and a normal chest radiography. Physicians should be aware of this entity during the differential diagnosis of respiratory symptoms in patients receiving treatment with interferon due to its high morbimortality and good resolution and outcome after drug withdrawal.