Objective. To determine the presence of bacteria type Helicobacter spp., from gastric ulcers in horses. Materials and methods. Fourty horses, 28 males and 12 females (4-17, years) were included. The frequency of presentation of bacteria like Helicobacter spp, was analyzed in descriptive form by means of the urease test UT), Gram (GS) stain and whartin-starry stain. Variables considered were the total of animals, anatomical (gastric segment of the mucous one) area, sex and age. Results. It was found the presence of bacteria like Helicobacter spp., the 65.0% of the horses were positive to urease test, 75.0% of the horses were positive to the whartin-starry and 50% to Gram stain. Only 62.5% of the animals were positive in both tests (urease test and whartin starry); meanwhile, 50.0% were positive in three tests (urease test, whartin starry and gram stain). 22.5% of the animals were negative in all tests. All of the positive samples were taken in the glandular mucous, mainly at the level of the fundus and hole gastric. Bacteria were found in all studied groups and both sex, major positivity was observed in males to two tests or more. From microscopic point of view it was observed shape curve spiral bacteria compatible to Helicobacter spp. Ureasa test was moderate, un few positive specimens showed high number of bacteria by using Whartin Starry stain. Conclusions. The bacteria Helicobacter spp., were present in the gastric ulcers of horses. © 2010 Universidad de Córdoba.