Exploiting embryonic stem cell (ESC)-derived cardiomyocytes as a vital source for cell therapies and tissue engineering will depend on robust, large-scale production processes. Recently, we have reported stirring-controlled formation of embryoid bodies, enabling the generation of pure cardiomyocytes in 2-L scale. Expansion and differentiation of genetically engineered mouse ESCs was followed by antibiotic-based cardiomyocyte enrichment. Here we have investigated modification of various parameters aiming at process optimization in a 250-mL spinner flask system. Duration of the differentiation phase, timing of retinoic acid addition, and a slower medium exchange rate were found to be crucial to enhancing cardiomyocyte yield. Improved process conditions were consequently transferred to a 2-L controlled bioreactor. Employing a manual fill-and-draw medium change resulted in the formation of 0.86 x 10(9) cardiomyocytes in a single 2-L batch, thereby reproducing our previous findings. In contrast, an automated perfusion-based strategy enabled the production of 4.6 x 10(9) cardiomyocytes in a single run. This is significantly higher than previously reported and highlights the enormous process optimization potential in the scalable generation of ESC-derived cell lineages.