Large scale production of monoclonal antibodies has been accomplished using bioreactors with different length to diameter ratios, and diverse impeller and sparger designs. The differences in these physical attributes could result in dissimilar mass transfer, shear dynamics and mixing inside the bioreactor, which could lead to disparities in cell growth and antibody production. The impact of impeller design parameters on protein expression levels and subsequent antibody production has not been investigated in depth before. The purpose of this study is to understand the impact of rushton turbine and marine impeller designs on Chinese hamster ovary (CHO) cell growth and metabolism, and antibody production. The interaction of process and culture parameters with respect to antibody production and quality will also be discussed.