Cellulose, the most abundant polysaccharide in the biosphere, is conventionally described as a substance composed of Β-1,4-glucan chains aggregated by hydrogen bonds within and between the chains. Whereas the scientific literature presumes that cellulose is comprised solely of glucose, acid hydrolysis of native and regenerated cellulose from several sources releases not only glucose, but several oligosaccharides, mannose, galactose, s-inositol, iditol, and sorbitol. Cellulose isolated from cotton linters, cotton fiber from two Acala (Upland) cultivars, two Pima cultivars, bamboo fibers, white pine fibers, regenerated bamboo fibers, regenerated cellulose sponge, coconut fibers, ivory nut shavings, cotton fabric, and the commonly used cellulose standard, AvicelŪ were investigated. In all cases, similar products were released by sequential acid hydrolysis. Samples were subjected to repeated hydrolysis in 6N HCl until completely dissolved. The hydrolysis products were released in relatively constant proportions throughout the sequential hydrolyses. Previous reports of the presence of monosaccharides, other than glucose, in acid hydrolyzates of cellulose often have been attributed to sample contamination. We believe this is the first report that shows that constituents other than glucose are present in sequential, exhaustive degradations of the polymer. The consistent presence of these minor constituents throughout the entire course of the progress stages of hydrolysis is considered an indication that the constituents are present within the cellulose itself. The description of cellulose as a substance composed solely of glucose originates from 1921. This early work used techniques now recognized as not capable of identifying minor constituent monosaccharides in an acid hydrolyzate.