The title compound, C21H36O3, was obtained by treatment of cyclohexanecarbaldehyde with catalytic toluene-4-sulfonic acid monohydrate. This redetermination results in a crystal structure with significantly higher precision than the original determination [Diana & Ganis (1963). Atti Accad. Naz. Lincei, 35, 80–88]. The asymmetric unit contains one sixth of the molecule, the formula unit being generated by crystallographic 3m symmetry. In the molecule, the trioxane and cyclohexane rings are in chair conformations. In the crystal structure, molecules are linked by weak C—HO hydrogen bonds along the  direction.