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The ultrastructure of the urinary bladder in selected species of lizards, turtles, tortoises, toads, and frogs was examined using light, scanning electron, and transmission electron microscopy. In all lizards examined, ciliated cells were found on the luminal surface of the tubular stalk that attaches the bladder to the cloaca but were absent in the body of the bladder. Cilia were not found in the bladder or stalk of fresh-water frogs. Cilia were likewise absent from the bladder stalk of fresh-water turtles but were present in the stalk of the terrestrial box turtle (Terrapene carolina) and the desert tortoise (Gopherus berlandieri). In all species tested, beating of the cilia in the stalk moved particulate matter toward the cloaca. Staining of the bladder of Anolis carolinensis with alcian blue demonstrated the presence of mucopolysaccharide-secreting cells that were scattered among the ciliated cells in the stalk of the bladder but were absent from the body of the bladder. Cilia appear to be found principally in the urinary bladder stalk of reptiles that are partially or entirely terrestrial and that also produce urate as a major nitrogenous waste product. The cilia in the bladder stalk, together with a mucopolysaccharide layer, may comprise a mucociliary transport system that moves particulate matter such as urate from the bladder into the cloaca.