Rice yellow stem borer (Scirpophaga incertulas), a monophagous pest, is the most destructive pest causing 3 to 95% yield losses in India. Though it accounts for 50% of insecticides used in rice fields, their typical internal feeding behaviour necessitate other management options. In the present study, the extent of natural egg parasitization was assessed on yellow stem egg masses collected from rice fields of Paddy Breeding Station, Coimbatore. Egg masses were collected during September (2016) to May (2017) and the influence of weather parameters on parasitization was observed. Seasonal variation on total egg mass parasitization of yellow stem borer recorded highest parasitization during the first fortnight of December (92.31%) and lowest or no parasitization during the month of May. Individual egg parasitization on yellow stem borer revealed the maximum parasitization of Telenomus dignus in the second fortnight of September (30.82%), T. schoenobii in the second fortnight of April (54.55%), T. japonicum during the second fortnight of November (7.86%) and Trichomalopsis sp. in the second fortnight of February (2.5%).