Cysts containing one or more physalopterid larvae were found commonly in the gastric tissues of snakes (Elapidae) and in all five families of lizards (Agamidae, Gekkonidae, Pygopodidae, Scincidae and Varanidae) in Western Australia. Snakes had been collected from many locations in tropical and arid Western Australia between 1912 and 1976, and lizards from the Great Victoria Desert between September 1978 and March 1979. Most cysts occurred in the submucosa; others were found within stomach muscle, and subserosally on the external stomach surface. Encysted and apparently viable larvae were associated with minimal host inflammatory response. Encysted dead and degenerating larvae occurred in cysts with inflammatory cell infiltrates, principally in snakes.