The water buffalo (Bubalus bubalis) is important to the economy of several countries in Asia, and South America and there are also isolated herds in Europe. In India, buffalo is the main dairy animal. Coccidiosis due to Eimeria is an important cause of diarrhea in livestock worldwide. Eimeria species are generally considered host specific. More than 11 Eimeria species are considered common in buffaloes and cattle (Bos taurus, Bos indicus). Of the numerous species of Eimeria in cattle, Eimeria bovis, Eimeria zuernii, Eimeria auburnensis and Eimeria alabamensis are considered pathogenic in cattle, but there is no report of their pathogenicity in naturally infected water buffaloes. Instead, Eimeria bareillyi has been documented to be the main pathogenic species in buffalo; it is not transmissible to cattle. There are many reports of Eimeria infections in water buffaloes, scattered in many local journals, and there are conflicting life cycle data on Eimeria species in buffalo. The objective of this paper is to summarize information on history, validity of Eimeria species, life cycle, pathogenicity, prevalence, epidemiology, diagnosis and control of coccidiosis in buffalo.