Abstract: AIM To find a new crystal structure of S-form in nateglinide N-(trans-4- isopropylcyclohexylcarbonyl)-D-phenylalanine. The XRD, IR patterns and data were given and the melting point was determined. METHODS Phase analysis was performed by X-ray powder diffraction, IR and elemental analysis and the melting point was determined by differential scan calorimetry. RESULTS S-form nateglinide is different from H-form or B-form. The melting point is 172.04℃. CONCLUSION The S-form nateglinide is a new crystal form.