The structural, electronic, and spectroscopic properties of methanediol in aqueous solutions have been studied by a combined approach based on Car–Parrinello molecular dynamics simulations and ab initio calculations. The hydrogen bond interactions between the solute and water have been characterized, showing the important role of the solvent in the stabilization of the methanediol conformers in solution. First insights on the experimental vibrational spectra have been obtained by the analysis of the simulation results, with particular regard to the most prominent band at 1050 cm–1 that has been attributed to both the symmetric and antisymmetric CO stretching modes. The assignment has been completed adopting both electric and mechanical anharmonic calculations considering the interactions with the solvent using a polarizable continuum model.