CELLULOSE XANTHATE is unusually effective in stabilising soil against attrition and deformation. At a concentration of about 0.1% in the soil it reduces erosion; at higher concentrations it can be used to bind soils to improve their mechanical strength. During an investigation of other uses for cellulose xanthate, we recently rediscovered its unusual interaction with soils. We describe here its formation and application in the laboratory, quantitatively compare it with several synthetic polymeric soil conditioners and suggest a mechanism for its action. With regard to the effectiveness of the xanthate soil treatment, its economy and the ready availability of agricultural waste cellulose, we hope to encourage further study of this interesting system.