Abstract The gas chromatographic and mass spectrometric properties of the trimethylsilyl derivatives of sugar phospates and related compounds were investigated because of the importance of these phosphate esters in intermediary carbohydrate metabolism. Aldose-1-, -4-, -5-, and -6-phosphates and ketose diphosphates were chromatographed as the trimethylsilyl derivatives of the intact phosphate esters; the trimethylsilyl derivatives of the aldose diphosphates were found to be too unstable for chromatography. Substituted oxime derivatives were prepared from several of the sugar phosphates in an attempt to reduce the number of gas chromatographic peaks (due to α- and β-furanose and pyranose structures) and to increase the stability. The trimethylsilyl derivatives of these oximes gave single peaks in many cases, but the separation of isomeric hexoses was poor. The methylene unit values were determined for forty-three sugar phosphates and related compounds on a polar (OV-17) and a non-polar (SE-30) phase. The structures of all derivatives were confirmed by mass spectrometry.