Bacterial cellulose (BC) has attracted attention for preparing advanced materials due to its microfibrous structure. In this study, quaternary ammonium bacterial cellulose (QABC) as well as quaternary ammonium plant cellulose (QAPC) as adsorbents for proteins have been prepared. Introduction of the quaternary ammonium group was conducted under different conditions to determine the best conditions for modification. The fibrous structures of QABC and QAPC were quite different and determined by the starting material. The adsorption capacities of hemoglobin and an anionic dye, thymol blue, on the adsorbents QABC and QAPC which were prepared under different conditions have been investigated. QABC showed a higher adsorption capacity for hemoglobin compared with QAPC, but a lower adsorption capacity for thymol blue.