Synthesis of citronellal to menthol using Pt/ZrO2-montmorillonite has been carried out. Menthol was important compound as feed and raw material for food additives, cosmetics and toiletries. Conversion citronellal to menthol by considering microwave assisted organic reaction through one-step reaction with a variety of irradiation times using catalyst Pt/ZrO2-Montmorillonite. Generally the conversion of citronellal to menthol can achieve by two separated reaction; cyclization and hydrogenation. Pt/ZrO2-montmorillonite catalyst made by immobilization method Pt from hexachloroplatinate. Characterization of the catalyst was performed by X-Ray Diffraction(XRD), BET (Brueneur Emmet Teller) surface area analyzer, Fourier Transform Infra Red (FTIR), Scanning Electron Microscope-Electron Dispersive Spectroscopy (SEM-EDS). Catalyst activity test performed on the conversion of citronellal to menthol using microwave assisted organic synthesis (MAOS). The resulting products were analyzed using Gas Chromatography (GC) to determine the total conversion and product  yield of menthol. The results showed that the total conversion of citronellal increased gradually with the irradiation times. But the selectivity of isopulegol and menthol product in lower irradiation time showed higher percentage compared to higher irradiation time. Highest menthol products at the time of irradiation of 10 minutes (4,4485%), however at the time of irradiation of 20 minutes menthol products does not obtained.  
Keywords: Menthol, Microwave assisted Conversion, Pt, ZrO2, Montmorillonite.