The Department of Guainía, in the Colombian Amazon, has a privileged situation in terms of biodiversity, but it remained for many years as one of the least explored territories of the country. Our contribution represents the result of several years of field collecting and taxonomic work in Guainía to increase the knowledge of the odonates there. We present here the first comprehensive checklist for Guainía with 104 species reported, of which 42 are new records for the department and 14 are new records for Colombia, including the rediscovery of the genus Hylaeonympha Rácenis, 1968. The updated number of Odonata reported for Colombia is now 513 species.