This document specifies a method for the determination of the ratio of stable isotopes of carbon (13C/12C) of sugars contained in honey by using liquid chromatography coupled to an isotope ratio mass spectrometer (LC-IRMS) for compound separation and subsequent determination of the 13C/12C ratio of mono-, di-, and trisaccharides. These ratios can be used to assess honey authenticity by comparing them to published guidance values of genuine honey as the 13C/12C ratios of sugars of genuine honey and sugars contained in adulterants (syrups made from starch-rich plants or from sugar cane or sugar beet) differ to a certain extent. The compliance assessment process is not part of this document.