<p>A method as described for the purification of a hydroxyphenylpropionic acid ester represented by the structural formula: (I). by means of recrystallization in a solvent mixture at a temperature lower than 40.degree.C. According to the method of the invention, the hydroxyphenylpropionic acid ester can be obtained as a white crystalline mixture of the .alpha. and .beta. crystalline form in good purity without the formation of the .gamma. crystalline form. The desired crystalline forms are easily confirmed by a characteristic X-ray diffraction pattern. The invention is very useful as an industrial method for the purification of the hydroxyphenylpropionic acid ester.</p>
