AbstractNitrogen‐15—hydrogen coupling constants between15N‐labeled oximes and α‐C‐protons,3J(15NH), of two series ofE/Zketoximes were studied in CCl4, CDCl3, CF3COOH, and DMSO‐d6.15N‐substituted‐methyl phenyl ketoximes constituted the first series and15N‐substituted‐methyl 2‐quinoxalinyl ketoximes the second series studied. Substituents in the first group were H, Me,t‐Bu, NMe2, OMe, Cl, Br and I; in the second they were H, NEt2, and Cl. |3J(15NH)| values for the isomers wherein the aliphatic substituent wasantito the oximino hydroxy group were always larger then those for thesynrelated isomers, permitting assignment of oxime stereochemistry to even a lone oxime diastereomer. Additionally, geminal nitrogen‐15—hydrogen coupling,2J(15NH) effects wer