Batch experiments were carried out to determine the capacity of Bacillus cereus biomass to adsorb Co(II) ions from aqueous solution with respect to pH, initial Co(II) concentration, contact time and biomass dose. The experimental data were modeled by Langmuir and Freundlich isotherm models. Langmuir model resulted in the best fit of the adsorption data. The maximum adsorption capacity for Co(II) was 68.10 mg/g. The best correlation was provided by the second-order kinetic model. The practical implication of this study is the development of an effective and economic technology for Co(II) removal from contaminated waters.