Seventy-four Oklahoma salamanders, Eurycea tynerensis, and 12 larval grotto salamanders, Eurycea spelaea, were collected from 4 stream sections of Sawmill Hollow Creek, Cherokee County, Oklahoma, and examined for monogenoids. Thirty-seven of 74 (50%) E. tynerensis were found to harbor Sphyranura euryceae. Fifteen of 25 (60%) of the E. tynerensis in the far-downstream section were infested by S. euryceae, 8 of 31 (26%) of the mid-downstream Oklahoma salamanders were infested, and 14 of 19 (78%) of the near-downstream E. tynerensis had the highest prevalence of S. euryceae. Analyses of variance with Fisher's least significant difference test of mean intensity of S. euryceae on E. tynerensis showed significant variation among groups. One of 2 (50%) E. spelaea from the near-downsteam section harbored S. euryceae; none of the 10 E. spelaea from the pond inlet were infested. We report the first population study of S. euryceae in E. tynerensis and a new host record for this monogenoidean in E. spelaea.