The name, helminthiasis of the intestinal wall, is proposed for pathological conditions resulting from invasion of the wall of the intestine by worms. This helminthic invasion leads to destruction of tissue, especially in the submucosa, hemorrhage, and concomitant inflammatory reactions. A description is given of 5 further cases of helminthiasis of the intestinal wall observed in autopsies in Batavia, Java, and caused by Ancylostoma duodenale. Necator americanus, by far the most common hookworm in Java, does not show this invasive power. Invasion of the intestinal wall usually takes place in the jejunum, but it may also occur in the ileum or even in the colon. There is no proof that the lesions thus produced endanger directly the life of the host.