Temporary ponds maintained by rainfall are used be several anuran species for reproduction, despite the possibility of eggs and tadpoles being exposed to large variations in environmental factors such as temperature, dissolved oxygen, pH. Furthermore, such temporary ponds may dry out without new rainfalls and suffer from aquatic hypoxia or even anóxia. Tadpoles switch from exclusive aquatic gas exchange, using gills and integument, to bimodal gas exchange due to the development of lungs used for air breathing. Tadpoles from species reproducing in temporary ponds would benefit from an early appearance of functional lungs during development, since they could supplement their metabolic oxygen demands by air breathing during phases of aquatic hypoxia/anoxia. To investigate this, we performed CT scans (at the Center for Biodiversity Documentation, Department of Biology, FFCLRP, USP) of tadpoles (Gosner stages 25-27) from nine species obtained from different collections. Tadpoles contrast was enhanced by immersion into PTA and the presence or absence of lungs was verified. As results, we observed the presence of lungs in tadpoles of the species of the family Leptodactylidae (Leptodactylus latrans, L. labyrinthicus, L. fuscus, Physalaemus nattereri, Pseudopaludicola falcipes), the family Hylidae (Boana albopunctata and Scinax fuscovarius), but not in tadpoles from species of Bufonidae (Rhinella icterica and R. diptycha). Our preliminary analysis shows that species reproducing in environments prone to dehydration seem to develop their lungs early, allowing for an early onset of bimodal gas exchange in these species. The amount of actual pulmonary gas exchange happening in lungs present in these early stages of development, however, need still to be quantified.