Synthesis of 5-amino-1-(beta-D-ribofuranosyl)-1H-tetrazole and 5-amino-2-(beta-D-ribofuranosyl)-2H-tetrazole is described. X-Ray crystallography was first used to establish the stereochemical configuration of the two isomers. By conducting 13C NMR analysis on these isomers with known structures, i.e., N1beta, a correlation is developed for determining the N-ribosyl attachment site of tetrazole ribonucleosides. Results are also presented on antiviral testing of these synthetic 5-aminotetrazole ribonucleosides against influenza A2/Asian/J305 virus infection in mice.