A capacitive sensor for saccharide detection is described in this study. The detection is based on selective interaction between diols and aminophenylboronic acid (APBA) immobilized on a gold electrode. Glucose, fructose, and dextran (MW: 40kDa) were tested with the system over wide concentration ranges (1.0 x 10(-8) M - 1.0 x 10(-3) Mfor glucose, 1.0 x 10(-8) M - 1.0 x 10(-2) M for fructose and 1.0 x 10(-10) M - 1.0 x 10(-5) M for dextran). The limits of detection (LODs) were 0.8nM for glucose, 0.6nM for fructose, and 13pM for dextran. These data were comparable to the others reported previously. In order to demonstrate glycoprotein detection with the same sensor, human immunoglobulin G (IgG) as well as horseradish peroxidase were used as model analytes. The sensor responded to IgG in the concentration range of 1.0 x 10(-13) M - 1.0 x 10(-7) M with a LOD value of 16fM. The performance of the assay of peroxidase was compared to a spectrophotometric assay by determining the enzymatic activity of a captured analyte. The results showed that the method might be useful for label-free, fast, and sensitive detection of saccharides as well as glycoproteins over a wide concentration range.