The constant stress elongation or creep of single filaments of American Delta cotton, crop of 1935-36, has been measured at relative humidities ranging from 0% to 100% and at a temperature of 28° C. The cotton is similar to the rayons of the cuprammonium and acetate types in that for certain, ranges the extension, e = k log t +c, but the constant k tends towards smaller values with increasing time, while in the acetate rayon the reverse is true.