Abstract: To overcome the weakness of glass electrode in response lag to H+-activity in turbid and viscous chitosan solution, antimony electrode was used as indicator electrode forming an indicator pair with tungsten electrode as reference electrode in the rapid coulometric titration of degree of de-acetylation of chitosan. The titration of a chitosan sample was completed within 5 min. The proposed method was used to the analysis of 5 chitosan samples. Results of degree of de-acetylation of chitosan found by this method were quite close to those found by 1H-NMR.