Symptoms of ornithosis are often unspecific and vary in severity. This case report illustrates the challenges in diagnosing ornithosis. It also shows how easy it is to diagnose ornithosis by PCR analysis of a sputum sample and that it is not always possible to base the diagnosis on serology as our patient had negative serology tests even four weeks after hospitalization. The diagnosis was furthermore compounded by an underlying chronic lung disease. To diagnose patients with respiratory problems correctly it is important to analyse lower respiratory samples by PCR along with other diagnostic tests and to get a detailed medical history.