The present disclosure relates to a novel class of anti-CD20 monoclonal antibodies comprising a homogeneous population of anti-CD20 IgG molecules having the same N-glycan on each of Fc. The antibodies of the invention can be produced from anti-CD20 monoclonal antibodies by Fc glycoengineering. Importantly, the antibodies of the invention have improved therapeutic values with increased ADCC activity and increased Fc receptor binding affinity compared to the corresponding monoclonal antibodies that have not been glycoengineered.