Chitosan-based polymeric surfactants (CBPSs) were prepared by N-acylation of chitosans (chitosan 10 and 500) with several acid anhydrides such as hexanoic (C 6 ), lauric (C 12 ), and palmitic (C 16 ) anhydrides. Among the CBPS samples, CBPSs having a good solubility at pH 4.0 were selected and observed for viscosity, surface tension, and adsorption of heavy metals (Cd 2+ , Co 2+ , Cr 2 O 7 2− , and Pb 2+ ) as well as the fatty acid (n-octanoic acid). The 1 H NMR spectrum of chitosan 10 modified with C 16 at the substitution ratio of 0.4 (CBPS 10 –C 16,0.4 ) showed 85% of acylation in 1% DCl/D 2 O solutions. CBPS 10 with the substitution ratio less than 0.4 showed a good solubility because of shorter repeating units and lesser amounts of hydrophobic substituents. The intrinsic viscosity of CBPS 10 was slightly increased, while that of CBPS 500 was decreased. As the substitution ratio and length of the carbon chain increased, the surface tension of CBPS 10 tended to decrease. CBPS 10 –C 16,0.2 had high adsorption ability for cationic metal ions such as Cd 2+ , Co 2+ , and Pb 2+ comparable to chitosan. Interestingly, CBPS 10 –C 16,0.2 showed a unique pH optimum for the anionic metal ion such as Cr 2 O 7 2− . In addition, CBPS 10 –C 16,0.2 exhibited the highest adsorption ability for n-octanoic acid among the tested CBPS 10 with different carbon chains.