To obtain a new hydroxy-methyl-hexanone useful for imparting a roasted brown flavor to foods or drink products.

2-hydroxy-5-methyl-hexan-3-one of formula I. The compound of formula I is obtained by (A) reacting 5-methyl-2-hexanone with sulfuryl chloride preferably a molar ratio of 1:1 to 1:1.5 between room temperature and a refluxing temperature, (B) treating the obtained 3-chloro-5-methyl-2-hexanone with potassium acetate and an alkali metal iodide in an insert solvent such as acetone, (C) hydrolyzing the obtained 3-acetoxy-ketone under an alkaline condition and subsequently purifying the obtained 3-hydroxy-5-methyl-2-hexanone of formula II or the mixture of the 3-hydroxy-5-methyl-2-hexanone of formula II with the 2-hydroxy-5-methyl-3-hexanone of formula I.