Removal of Mn(II) ions from aqueous solution throug h adsorption on to Tamarindus Indica Fruit Nut Shell (TFNS) in its pristine and acid treated f orms was studied. TFNS a tannin-containing material was characterized by porosity, SEM and FTI R analysis. Experiments were carried out as function of pH, concentration of metal ion, amount of adsorbent and contact time. The equilibrium characteristics of Mn(II) adsorption wa s described by Freundlich and Langmuir isotherms. The kinetic data were fitted to pseudo-f irst-order, pseudo-second-order, chemisorption, fractionary order and Weber-Morris m odel. Based on error function analysis, it may be concluded that pseudo-second-order and chemi sorption models gave a better representation of the data compared to other models . The monolayer adsorption capacities of pristine and acid treated forms of TFNS were found to be 122 and 182 mg/g respectively. A compression has been drawn on the extent of biosorp tion between pristine and acid treated form of TFNS. Due to their outstanding adsorption capaci ties, TFNS is an excellent adsorbent for the removal of Mn(II) ions.