The content and distribution of GAGs in the anatomic structures of pathological (pneumoconiosis, pneumonia, pulmonary embolism) and senescent lungs have been measured. The total GAG content of the lung structures, except central bronchi is generally lower than normal in the pathological lungs. The GAG distribution in the pleura (DS predominant), central bronchi (C6S predominant), arteries, veins and 'total lung' is similar to the corresponding normal distribution. The other notable observations are: the concentration of HA in peripheral bronchi and alveoli is increased possibly in response to the high local concentration of coal dust; an age related GAG switch from DS in the arteries of the young to C6S in the arteries of the mature lung is confirmed; the arterial GAG content generally increases with age up to age 103 in the male; the arteries of a female smoker display the mature male pattern of GAG composition. The data suggest that gender, smoking and age, more than acute pathology, determine the GAG composition of the anatomic structures of the lung.