Many species of opossums are created and used in laboratories, opening a wide field for studying and acquiring knowledge about the habits, diseases, diet and reproduction of these animals. The research aimed at describing the macroscopic and microscopical morphology of the trachea and larynx of opossums. In this study, five opossums (Didelphis sp.) were used. The trachea and larynx of the opossums were extracted, measured and processed by histology routine and dyed with Hematoxiline eosine, Picrosirius and Masson´ Trichrome. The larynx can be divided into: cricoid in a "V"-like shape, thyroid in a shield-like shape, arytenoid in shell-like shape, and epiglottis shaped like sheets, the first three structures showed hyaline cartilage, and the last structure showed elastic cartilage. The trachea showed a cylindrical form and it consists of 25 cartilaginous incomplete rings in a "C"-like shape, similar to amphibians, snakes, lizards and pigs; and different from domestic animals.
arytenoid; cricoid; epiglottis; thyroid; tracheal rings