Little information is available concerning the nematode parasites of salamanders in California. Lehmann (1954) reported the finding of Oxyuris dubia Leidy 1856, in the rectum of 33 Ensatine e. Eschscholtzii from Sonoma County, California, and in 3 of 10 Batrachoseps a. Attenuatus, from San Francisco County, California. He also reported Oxyuris magnivulvaris Rankin 1937 in the rectum of 1 to 2 Aneides flavipunctatus, from Marin County, California and Rhabdias sp., from lungs of 2 of 12 aquatic Triturus torosus from Contra Costa County, California. Lehmann (1960) reported O. dubia from the cloaca of 1 Aneides flavipunctatus and 3 Aneides lugubris taken in Marin and Sonoma Counties, California. Several similar studies have been made in other states citing the occurrence of nematodes in various species of salamanders. There is an even greater paucity of information concerning parasitism in those salamander species inhabiting the western slope of the Sierra Nevada. This investigation is concerned with the four most common salamanders of the central California clopes, Aneides lugubris Hallowell, Batrachoseps attenuatus attenuatus Eschscholtz, Ensatina eschscholtzii platensis Espada, and Taricha torosa sierrae Twitty. Individuals of these species were collected and examined for parasites over the fall, winter and spring months, commencing in the fall of 1960 and extending through the spring of 1962. Data were collected to determine what nematode species inhabit these hosts and to ascertain the incidence and sites of infection. An attempt was also made to determine whether time of year, environmental conditions, and geographic distribution are of particular significance in the host-parasite relationships studied. A second group of salamanders which included Aneides lugubris Hallowell and Taricha torosa Rathke was examined. Both of these species were taken in a coastal region and were used as a comparison group Special attention has been directed to the study of Oxyuris dubia Leidy, 1856, with the intent of clarifying Leidy’s description of this species. This nematode is a frequent parasite of the salamanders studied, and special consideration has been given to the culturing of their eggs in an attempt to better understand the pattern of development.