Strongyloides stercoralis, one of the intestinal nematode species, is soiltransmitted and endemic in tropical and subtropical climates. Its infective larvae penetrates the skin, enters the venous system, travels to the heart and lung,migrates up to the esophagus, is swallowed, and finally reaches the small intestine. Manifestations of infection can be asymptomatic or clinically inapparent.Gastrointestinal symptoms of strongyloidiasis include diarrhea, nausea, vomiting, anorexia, abdominal bloating and pain. In immunocompromised patients,hyperinfection or disseminated strongyloidiasis may occur. Clinical diagnosis of strongyloides stercoralis is usually made by stool examination to detect the rhabditiform larvae or eggs. However, stool examination is insensitive due to the low parasite load and the irregular larval output. We report a 64-year-old woman working in farming with a chief complaint of gastrointestinal discomfort. Infection of strongyloides stercoralis was not detected by stool examination the first time. Strongyloidiasis was confirmed by pathological diagnosis, and the specimens were taken by colonoscopic biopsy.