3,5-bis(hydroxymethyl)tetrahydro-4H-pyran-4-one by condensation of acetone with formaldehyde in the ratio of 1:4 in an alkaline medium at a temperature of 30-35°С (product yield 67.4%) was obtained. To determine the composition of obtained compound elemental analysis was used. Functional composition and structural elements were identified using IR spectroscopy. To prove the structure of the synthesized compound, 1H and 13C NMR spectra were taken on a JNN-ECA Jeol 400 spectrometer (at a frequency of 399.78 MHz and 100.53 MHz) with a CDCl3 solvent. Quantum-chemical calculations of stable conformations of 3,5-bis(hydroxymethyl)tetrahydro-4H-pyran-4-one was performed using ab initio DFT B3LYP method and 6-31G (d) and 6-311+G(3df,2p) basis sets. It was found that the stable conformers obtained by calculations are in the "chair" conformation; the hydroxymethyl substituents in conformer I are located equatorially, in conformation II – axially and equatorially, in conformation III – axially. In the conformer III, as a result of spatial proximity, hydroxymethyl substituents form an intramolecular hydrogen bond. The total energies and dipole moments were calculated; a lower value of the dipole moment of the conformation II may indicate its preference over the others.