This study was aimed at evaluating the presence of equineherpes virus 1 (EHV-1) and 4 (EHV-4) antibodies in equine populations from the Colombian Orinoco region. Cross-sectional serological sampling was thus used on horses (n: 260) from 6 localities in the region. An ELISA test was used for analysing the samples, using a commercial kit which discriminated antibodies regarding both viruses; 12.7% seropositivity was found for EHV-1 and 70.4% for EHV-4. All the horses found seropositive for EHV-1 were also seropositive for EHV-4. EHV-1 seropositivity by municipality was as follows: San Martin 34.6%, Arauca 10.4%, Puerto Lopez 8.7%, Yopal 6.3%, San Jose del Guaviare 4.9% and Puerto Gaitan 4.0%. EHV-4 seropositivity for ARTICULO ORIGINAL/ORIGINAL ARTICLE