Coccidiosis (Eimeriosis sensu stricto) of small ruminants is a protozoan infection caused by several species of the genus Eimeria which develop in the small and the large intestine, affect young animals in particular and are specific for each host. Eimeria ovinoidalis in sheep and Eimeria ninakohlyakimovae in goats are the most pathogenic species. Coccidiosis is of great economic importance because of the losses due to clinical disease (diarrhoea) but also because of subclinical infections (poor weight gain in particular). Oocyst excretion is at the maximum around the weaning period and shows a steady decline afterwards due to a strong immunity. Risk factors for high excretion include breeding intensification, high stocking rates in premises, poor hygiene and all causes of stress (physiological, nutritional, etc.). Reliable diagnosis include combined clinical, epidemiological, necropsic and coproscopical approaches. Control is mainly based on hygienic measures between lambing/kidding and weaning periods and on anticoccidial compounds use.