In previous work, we have shown that photoexcitation of guanine cation radical (G(center dot+)) in frozen aqueous solutions of DNA and its model compounds at 143 K results in the formation of neutral sugar radicals with substantial yield. In this report, we present electron spin resonance (ESR) and theoretical (DFT) evidence regarding the formation of sugar radicals after photoexcitation of guanine cation radical (G(center dot+)) in frozen aqueous solutions of one-electron-oxidized RNA model compounds (nucleosides, nucleotides and oligomers) at 143 K. Specific sugar radicals C5'(center dot), C3'(center dot) and Cl'(center dot) were identified employing derivatives of Guo deuterated at specific sites in the sugar moiety, namely, Cl'-, C2'-, C3'- and C5'-. These results suggest C2'(center dot) is not formed upon photoexcitation of G(center dot+) in one-electron-oxidized Guo and deuterated Guo derivatives. Phosphate substitution at C5'- (i.e., in 5-GMP) hinders formation of C5'(center dot) via photoexcitation at 143 K but not at 77 K. For the RNA-oligomers studied, we observe on photoexcitation of oligomer-G(center dot)+ the formation of mainly Cl'(center dot) and an unidentified radical with a ca. 28 G doublet. The hyperfine coupling constants of each of the possible sugar radicals were calculated employing the DFT B3LYP/6-31G* approach for comparison to experiment. This work shows that formation of specific neutral sugar radicals occurs via photoexcitation of guanine cation radical (G(center dot+)) in RNA systems but not by photoexcitation of its N1 deprotonated species (G(H)(center dot)). Thus, our mechanism regarding neutral sugar formation via photoexcitation of base cation radicals in DNA appears to be valid for RNA systems as well.