Among 1067 gastroenterologic out-patients examined in the years 1966–1968, Entamoeba histloytica (EH) and Dientamoeba fragilis (DF) alone or in combination, were found in 362. Of the 309 patients harbouring EH (alone or with DF), 163 or 53% presented the clinical syndrome of chronic recurrent intestinal amoebiasis. DF alone may be the cause of intestinal irritation necessitating anti-amoebic treatment. The two amoebas were found much more in stool specimens following a purgative than in spontaneous stool, and even better results were obtained from material taken at rectoscopy. The cultural method increases considerably the chances of detecting amoeba but the concurrent use of microscopic and culture techniques yield the best results. There has been practically no change in the incidences of chronic amoebiasis in the sampled population over the last 10 years.