The physical structure and chemical composition of the cotton-seed were examined with special interest focused on the attachment of cotton fibers to the seed coat. Hand-cut cross sections of the seed coat showed six layers distinctively: outer epidermis, outer pigment, color-less, palisade, inner pigment, and inner epidermis layer. The structure between the fibers and the seed coat was studied using optical microscopes and a scanning electron microscope. The fibers were located between outer epidermis cells and the roots of the fibers were attached to the surface of the outer pigment layer. Microtomed thin sections were used to identify chemical compositions of the layers. A series of stains was chosen to identify the chemical components such as lignin, tannin, lipid, and pectin in the seed coat. Ruthenium Red, which stains pectin, was of particular interest because the Ruthenium Red stained between the outer epidermis and the fiber shank. The results suggest that pectin is the material bonding fibers to the seed coat.