Abstract: One hundred and twenty grass carp, Ctenopharyngadon idella, were examined over a period of one year from March 1998 to February 1999 at Government Fish Hatchery, Mian Channu, Punjab, Pakistan. Four species of copepod ectoparasites recovered were Lernaea (L.) polymorpha (Yu, 1938), L. cyprinacea (Linnaeus, 1761), L. lophiara (Harding, 1950) and L. ctenopharyngodonis. The parasitic infestation was low during the summer months when temperature ranged between 30-32°C and highest in winter months when temperature was between 13-23°C.