Abstract: In this work, a laser scattering method was used for measuring the optical properties of dental caries using He-Ne laser. A spectrometer setup was built to test the optical characteristics of the molar tooth decay. The measurements yield the reflectance, absorbance and the transmittance of sound and decayed tooth. Monte-Carlo simulation was used to investigate and provide further analysis of the resultant measurements of the spectrometer. The results differentiate between sound and caries and enable to predict the exact localization of source-detector pair relative to the examined tooth, in order to help in performing optical imaging for in-vivo early detection of caries.