A method to discriminate between solid and liquid velocities in a refractive index matched solid-liquid slurry flow has been developed. The matching of the refractive index of the solid and liquid allows the use of non-intrusive two color backscatter mode laser Doppler velocimeter (LDV) to measure the local solid and liquid velocities. A horizontal pipe flow configuration is used. Silica gel particles of mean diameter 40 mu m and 50% sodium iodide solution are used as the refractive index matched solid and liquid, respectively. A signal processing technique which utilizes histograms of velocity along with signal amplitude discrimination is developed for differentiating between the solid and liquid velocities in the refractive index matched slurry. The technique utilizes the peaks in the velocity histogram that are associated with the local solid and liquid velocity data. Signal amplitude discrimination is used for identifying the histogram peaks associated with the solid and liquid velocities respectively and obtain the velocity distributions for the solid and the liquid in the histogram. This technique has been successfully applied to the slurry flows of low turbulence intensity (less than or equal to 10%) with volumetric concentration as high as 25% in the heterogeneous and saltation flow regimes.