Thelazia callipaeda is a slender, long, and cylindrical nematode which parasitizes in the conjunctival sac of human and causes conjunctivitis. The animals such as the dog, rabbit, horse, deer, and cow were revealed as its reservoir and some species of the fly suspected as its vector. We experienced a case of T. callipaeda isolated from human conjunctival sac of a 41-year old man who lived in Wanju-gun, Chonbuk province and raised the dogs. He complained of an irritation, itching and foreign body sensation on his right eye and the two worms were picked out of his right eye by forceps from conjunctival sac. General features of the worms were ivory colored and slender. Two worms were 15.2mm and 15.8mm in length and both have less than 1.0mm in maximum width. Microscopically, both of the worms were female. The vulva opening of the worms located anterior to esophago-intestinal junction. The uterus filled with the eggs and larvae encysted with oval membrane. The buccal cavity in head portion was tetrazoid and connected with well-developed esophagus. At the tails of the worms, anus and papillae were observed. Characteristic compact cuticular transverse striations were identified on the whole body surface. (Korean J Clin Microbiol 1999;2:207-211)