Endometritis is the main cause of reduced reproductive efficiency in mares destined for foal breeding. This being a persistent inflammation in the uterus that may be accompanied by opportunistic and/or venereal infectious agents (1). Streptococcus zooepidemicus is the main agent isolated in cases of endometritis (2). The disease can occur after calving or during insemination or mating, causing a significant problem for both horse breeders and veterinarians (3). Therefore, this review seeks to consolidate the current information on equine endometritis, emphasizing the diagnostic methods with the best results in clinical practice, supported by recent scientific articles