Background: Domesticated animals are exposed to antibiotics used in veterinary medicine or as feed additives. Over 4 centuries ago, goats were brought by the Spaniards to the Caribbean island of Mona, and have lived since then lived with very low human impact. The aim of this work was to determine the presence of antibiotic resistance genes in fecal bacteria from feral goats from Mona Island. Methods: We sampled feces from 5 Mona Island feral goats, and from 5 domestic goats from a farm in main land Puerto Rico. Fecal DNA was isolated using the MoBio Powersoil kit. PCR was used to amplify tetracycline resistance genes tet(M), tet(O), tet(Q), tet(S) and tet(W). Results: All feral and domestic goats harbored intestinal bacteria with tet(O) and tet(W) and none had tet(M) or tet(S). Domestic goats harbored in addition tet(Q). Conclusion: These results confirm that even animals with no or very low exposure to antibiotics, harbor intestinal bacteria with antibiotic resistance genes. In goats, domestication practices increase the number of tetracycline antibiotic resistance genes in the intestinal bacteria.National Science Foundation, HRD #0734826 University of Puerto Rico, Central Administration and Río Piedras Campus