Highly pure monomeric ω-hydroxycarboxylic acids (HCAs) with gC 6 are prepared from their corresponding lactones or alkyl ω-hydroxycarboxylates through saponification followed by H 2 SO 4 acidification and treatment at 35-40 °C/8-12 mbar or by freeze-drying. The HCA is being formed through its sodium or potassium salt and is obtained in 80-85% yield with >99.5% purity, uncontaminated with dimers. This simple procedure excludes chromatographic purification.