Interest in the field of antibody—drug conjugates (ADCs) has grown exponentially over the past decade. As the product pipeline grows, there is increasing need for robust chemistries which allow selective and efficient functionalization of the antibody cores for introduction of appropriate linkers and spacer groups. Under conventional bioconjugation conditions, product heterogeneity often results, and the drug-to-antibody ratios (DAR) are inconsistent. Based on our experience in protein derivatization, we have investigated the potential for continuous-flow microreactor technology to expedite and facilitate such processes. We demonstrate its potential using reagent proteins and the chimeric monoclonal antibody infliximab (Remicade™).