The batch-wise biosorption of cobalt by Ficus religiosa (peepul) leaf powder has been carried out. The optimum biosorbent dosage is 60 g/L for an equilibrium agitation time of 90 min. Percentage removal of cobalt is increased from 70.9 to 97.2 (0.96 to 1.45 mg/g) with decrease in acidity in the pH range from 2 to 7. The experimental data are. well represented by Freundlich (n=0.42, K(f)=0.83 L/g, R(2)=0.948), Langmuir (R(L)=0.566, q(m)=3.60 mg/g, R(2)=0.991), Redlich-Peterson(R(2)=0.98) and Temkin (R(2)=0.98, b(T) =784.52) isotherms, indicating favourable biosorption. The biosorption of Co(II) is described by the pseudo-second order rate equation (K=0.418 g/mg-min, R(2)=0.99) preferably than first order rate equation (R(2)=0.89). The biosorption is exothermic, irreversible and spontaneous.