The electron impact mass spectrum of 3-cyclohexen-1-ol has been studied, especially with regard to the retro Diels-Alder reaction. Six deuterium labelled analogues and two dimethyl substituted homologues were synthesized. Contrary to what we have observed with 2-cyclohexen-1-ol, the double bond migration which precedes the retro Diels-Alder reaction plays a minor role.