A fiberoptic laryngoscope which allows direct visualization of the deep pharynx and epiglottis has been developed for transoral tracheal intubation of small laboratory mammals. The device has been employed in the intubation and instillation of a variety of substances into the lungs of rats, and with minor modification, has had similar application in mice, hamsters, and guinea pigs. The simplicity and ease of handling of the laryngoscope permits one person to intubate large numbers of enflurane anesthetized animals either on an open counter top or in a glove-box, as may be required for administration of carcinogenic materials. Instillation of 7Be-labeled carbon particles into the lungs of mice, hamsters, rats, and guinea pigs resulted in reasonably consistent interlobal distribution of particles for each test animal species with minimal tracheal deposition. However, actual lung tissue doses of carbon exhibited some species dependence.