Studies dealing with the role of the skin, lungs, and buccopharyngeal cavity in respiration in salamanders (Whitford and Hutchison, 1963, 1965, and 1966) have been confined to an analysis of gas exchange in an air environment. In the semidesert and desert areas of the Southwest, populations of the tiger salamander, Ambystoma tigrinum, spend much of their life in semi-permanent or permanent bodies of water. Consequently, an evaluation of the role of the various respiratory surfaces in this species must be conducted in an aquatic environment to determine the role of the skin, lungs, and gills in aquatic respiration when the animals are able to obtain atmospheric oxygen by surfacing. In New Mexico some populations are composed of both transformed and neotenic adults (axolotls). The factors leading to the failure of metamorphosis are not know nor is the adaptive significance of neoteny in these populations understood. Studies of gas exchange in both life forms of adult A. tigrinum could aid in an interpretation of ecological and physiological adaptations to pond environments.