A quantitative research of parasites of 67 endemic frog Telmatobius jelskii (Peters, 1863) collected from Laguna Tucto (76°46'11"W, 10°39'11"S) where Pativilca River is originated was conducted, and was located in the Province of Oyon, high Andean area from the Department of Lima, Peru during September-October 2000. Of the frogs collected, 23 were females and 44 males. Male showed a length between 5.2 ± 0.5 cm (range = 4.0-6.4 cm) and female between 5.5 ± 1 cm (range = 3.9-7.6 cm) and were not found differences between both sexes. 86 specimens of parasite and three species in total during all the survey were collected. 28 hosts were infected (41.8%). twenty-five hosts (37.3%) showed infection with one parasite species, and three (4.5%) had two parasite species. Three parasite species were found: Gorgoderina parvicava Travassos, 1922 (Digenea: Gorgoderidae) (Prevalence = 40.3%; mean Intensity = 3.1; mean abundance = 1.2), Cylindrotaenia americana Jewell, 1916 (Cestoda: Proteocephalidae) (Prevalence = 3%; mean Intensity = 1; mean abundance = 0.02) and Aplectana hylambatis (Baylis, 1927) (Nematoda: Cosmocercidae) (Prevalence = 3%; mean Intensity = 1; mean abundance = 0.02). G. parvicava had an overdispersed distribution and was the dominant species. An effect of sex and length with prevalence and mean abundance of infection of G. parvicava was not found. The relationship of helminthes parasites with T. jelskii is discussed. G. parvicava and C. americana are new records for T. jelskii.