An annotated catalog of clinical and pathologic observations in an adult population with CF has been presented. The spectrum of disease is broad, and the diagnosis usually requires the demonstration of abnormalities in multiple systems. Tissues of each germ layer have been found involved in CF. Correlation of clinical and pathologic observations suggests that manifestations are essentially episodic and focal. In this population, the most characteristic abnormalities recognized by the pathologist are focal biliary cirrhosis, distinctive obstructive lesions of the male genital tract, prolonged staphylococcal or pseudomonas colonization of respiratory secretions, and obstructive bronchopulmonary disease. Some form of pancreatic atrophy is usually present.