Specific surface areas of 6 coton fibers from ICCS were estimated by the methylene blue adsorption. The adsorption isotherm was done at 25°C during 24 h. This condition was obtained from the kinetic study of this dye on the cotton fibers previously. The concentration of methylene blue used, in the range 0.004 - 0.32 g l-1, was analysed by spectrophotometer at the wavelength 660 nm. The surface areas of these cottons, B-26, C-36, D-5, E-4, G-17 and I-26 were found 32.3, 32.4, 34.4, 5.72, 43.9 and 29.9 m2 g-1 respectively. There is relationships between these surface areas and their fineness analysed by FMT 3 (Fineness Maturity Tester 3, by Shirley Dev. Lim.). A numerical relationship of the form a+bH-1 has been obtained by nonlinear regression computerized software.