Carbon dioxide as a refrigerant is becoming increasingly more popular globally. With thousands of commercial transcritical systems running worldwide, much knowledge and experience have been gained on this topic. Indeed, these systems can be employed in many larger applications. However, large commercial systems have increased complexities; not just larger capacities, but also longer pipe runs and/or more dramatic load shifts. These factors should drive a transcritical CO2 system designer to consider additional measures. In this paper, we first discuss oil management considerations for commercial systems and then explain some of the unique challenges that large commercial systems might find and offer potential solutions as to how to solve them. In addition, the selection and sizing of the components discussed here is paramount to ensure proper compressor lubrication and maintain high levels of heat transfer and efficiency while removing as much oil as possible from the refrigerant.