Low resolution mass spectra of cyclohexane‐1,2‐diols and of deuterium labelled cyclohexane‐1,2‐diols cis and trans have been measured. The results indicate that it is easy to differentiate between positional isomers and that the stereochemistry of cyclohexane‐1,2‐diols can be deduced from the mass spectra. In the 1,2‐diols the elimination of water under electron impact occurs simultaneously in three ways: (a) between an OH group and a H atom in position 1,4, (b) between the two OH groups, (c) without participation of the II atoms of the OH groups. Difficulties encountered in deducing unambiguous fragmentation patterns are discussed.