The use of Au@SiO2 core/shell nanoparticle assemblage with highly sensitive SERS was investigated for the determination of glucose in this study. Rhodamine 6G (R6G) dye molecules were used to evaluate the SERS enhancement factor for the synthesized Au@SiO2 core/shell nanoparticles with various silica shell thicknesses. The core/shell assemblage with silica layer of 1-2 nm over a Au nanoparticle of ~36 nm showed the highest SERS signal. Our results show that the SERS technique is able to detect glucose with lower detection limits (LOD) and wide concentration ranges, i.e. 20 ng/dL to 20 mg/dL (10-12 – 10-3 M).