A representative mucilage, named Okra-mucilage R. was isolated from the roots of Abelmoschus esculentus MOENCH (=Hibiscus esculentus L. ; Okra). The final preparation was homogeneous as determined by ultracentrifugal analysis, cellulose acetate membrane electrophoresis, and gel chromatography. Its water solution gave an intrinsic viscosity value of 33.4. It was mainly composed of partially acetylated acidic polysaccharide, and its molecular weight was estimated to be about 1700000. The polysaccharide was composed of L-rhamnose : D-galactose : D-galacturonic acid : D-glucuronic acid : O-acetyl groups in the molar ratio of 1.1 : 1.9 : 1.0 : 1.0 : 2.0. Methylation and partial acid hydrolysis studies made it possible to deduce the structural features of the polysaccharide in the mucilage.