Multi-year samples of Hyla regilla from three California counties (Los Angeles, Orange, Riverside) as well as single-year samples from three additional California counties (Humboldt, Imperial, Santa Clara) were examined for helminths. Gravid individuals of one species of cestode, Distoichometra bufonis and two species of nematodes, Oswaldocruzia pipiens and Rhabdias ranae were found. Metacercariae of two species of trematodes, Alaria sp. and Clinostomum sp. and larvae of one nematode species, Physaloptera sp. were also found. Of the helminths found in the multi-year samples, only O. pipiens was persistent; however, it was not stable.