AbstractTwo novel genotypes of species human mastadenovirus D designated 109 and 110 were isolated from three epidemiologically unrelated cases of acute respiratory disease detected in January 2018 by surveillance efforts at the California/Mexico border. Both genotypes represent examples of intertypic recombination. Genotype D109 is most closely related to genotype D56 (97.68% genomic similarity) and features a type D22‐like penton base, a type D19‐like hexon gene, and a type D9‐like fiber [P22/H19/F9]. On the other hand, genotype D110 is most closely related to type D22 (96.94% genomic similarity) and features a type D67‐like penton base, a novel hexon gene, and a type D9‐like fiber [P67/H110/F9]. Importantly, the fibers of both novel genotypes are highly similar to those of genotypes D56 and D59, which have also been isolated from a few cases of respiratory infections. The present report shows data contributing to the understanding of the molecular determinants of the expanded tissue tropism of certain members of species HAdV‐D.