A new selective two-step synthesis of β-isothiocyanato ketones from α,β-unsaturated ketones has been developed. This synthesis includes preparation of β-azidoketones with subsequent reaction of these with triphenylphosphine and carbon disulfide. This approach is especially useful for synthesis of β-unsubstituted β-isothiocyanato ketones, which are impossible to prepare with sufficient purity via commonly used procedures.