Two model functions with broad distribution (Mw/Mn= 6.3) and narrow distribution (Mw/Mn= 1.22) were used in this paper. The effect of the broad and narrow distribution on the extent of correction of instrumental spreading has been examined. The calculated results showed that the differences of molecular weight

distribution of samples affect only the shape of chromatograms but not the extent of average molecular weight correction. The opinion prevailed in literature that peak broadening correction for samples wit broad mole-cular weight distribution is negligible in comparison with that of narrow molecular weight distribution is a misunderstanding.