The complete basis set method, CBS-QB3, is used in combination with two continuum solvation models for aqueous solvation to compute reduction potentials previously determined experimentally for 36 nitrogen oxides and related species of the general formula HVCWNXOYClZ. The PCM model led to the correlation E-exp(o) (vs NHE) = 0.84E(calc)(o) + 0.03 V with an average error of 0.12 V (2.8 kcal/mol) and a maximum error of 0.32 V (7.4 kcal/mol), The CPCM/UAKS model gave E-exp(o) (vs NHE) = 0.83E(calc)(o) + 0.11 V with the same average error. This general method was used to predict reduction potentials (+/- 0.3 V) for nitrogen oxides for which reduction potentials are not known with certainty: NO2/NO2- (0.6 V), NO3/NO3- (1.9 V), N2O3-/N2O32- (0.5 V), HN2O3/HN2O3- (0.9 V), HONNO, H+/HONNOH (1.6 V), 2NO,H+/HONNO (0.0 V), 2NO/ONNO- (-0.1 V), ONNO-/ONNO2- (-0.4 V), HNO,H+/H2NO (0.6 V), H2NO,H+/H2NOH (0.9 V), HNO,2H(+)/H2NOH (0.8 V), and HNO/HNO- (-0.7 V).