A method for producing 2-hydroxy-4-(methylthio)butyric acid which comprises the following steps (A), (B) and (C): Step (A): step of reacting 1,2-epoxy-3-butene with water to obtain 3-butene-1,2-diol, Step (B): step of reacting 3-butene-1,2-diol with methanethiol to obtain 4-(methylthio)butane-1,2-diol, Step (C): step of oxidizing 4-(methylthio)butane-1,2-diol to obtain 2-hydroxy-4-(methylthio)butyric acid.