Idiopathic pulmonary fibrosis (IPF) is a chronic respiratory disease with an estimated incidence of 3-6 cases per 100 000 inhabitants in Sweden. There is no cure for the disease, which inevitably leads to death. A similar disease has been found among terrier dogs, with an especially high prevalence in the West Highland White Terrier (WHWT). Dogs with pulmonary fibrosis become lethargic with exercise intolerance, and in some cases they develop cough and respiratory distress. This thesis gives a brief review of the field of pulmonary fibrosis and presents a method for analyzing surfactant proteins in bronchoalveolar lavage (BAL) in the dog.