Adhesion of white cells to microfilariae in vitro has been reported, but we found no record of cell adhesion to the cuticle of the larvae of Dracunculus medinensis. We noted adhesion of white cells to living and dead guinea-worm larvae in bleb fluid from four patients with guinea-worm disease, and in fluid aspirated from the joint cavities of 10 patients with acute guinea-worm arthritis. More cells were found adhering to larvae in lesions of long duration. No adhesion of white cells to living or dead larvae was found in fluids from hydrocele or in one case of microfilarial granuloma of the brain. This phenomenon is thought to be due to phagocytosis or to some other mechanism.