Attempts have been made to correlate estimates of molecular weight for a group of cationic polysaccharides known as chitosans between the highly popular technique of size-exclusion chromatography coupled to multi-angle laser light scattering, SEC-MALLS, and the less convenient but more established technique of sedimentation equilibrium in the analytical ultracentrifuge. Four pharmaceutical grade chitosans of various molecular weights and degrees of acetylation (430%) were chosen. Better correlation than previous was achieved, although some batch variability was observed. Despite the broad spectrum in degree of acetylation, a logs20,w versus logMw scaling plot appeared to fit a straight line with power-law exponent b=0.250.04, i.e. between the limits of rod (0.15) and coil (0.40.5), although this may be the average of a lower b value at low Mw and higher b at high Mw. With regard to viscosity, a log[] versus logMw scaling plot appeared to also fit a straight line with power-law exponent a=0.960.10, again between the coil (0.50.7) and rod (1.8) limits.