Nutritional status, measured as body condition, has been used to assess welfare in working equines. Dental abnormalities have a substantial impact on the nutritional status of equines because they limit digestibility of foods and then nutrient utilisation. In Mexico, most of the working equines show body condition scores below 2.5 throughout the year and teeth problems may have a role in this. The purpose of this work was to investigate the prevalence of dental disorders in a population of working equines in Mexico. The study was run within with the work of the mobile clinics of DS-ILPH-UNAM programme. A total of 3,838 equines in 47 rural villages were assessed. Data were collected by surveys and by recording dental disorders in a complete oral examination. Species (donkey, horse or mule), sex (male or female), age and body condition score of every animal was recorded. The prevalence of animals with dental disorders and the frequency of each dental pathology in the affected animals were calculated. Body condition and age of affected animals were recorded. The average prevalence of serious dental disorder was low in all the cases (13%) and did not differ among species and sexes. The most frequent condition affecting incisor line of occlusion was ventral curvature. Enamel points, hooks, ramps, accentuated transverse ridges and steps were the most frequent abnormalities of cheek teeth rows. The average age of affected animals was 10.4±5.8 years, ranging from two to 40 years. Age did not differ among species or sexes. Mules showed higher average age, but the range was narrower than in other species. With regards to the body condition, more than 60% of the affected equines were in the lowest range (<2.5). These results are the first to describe the prevalence of serious dental abnormalities in working equines in Mexico and suggest the subject deserves further investigation. The data would allow strategies aimed at improving equine welfare via nutritional status.