The scale-up of culture of adherent cells, such as Vero cells and fibroblasts, can be difficult. This study shows a process for scaling up Vero cell culture from static T-flasks and Thermo Scientific™ Nunc™ Cell Factory™ Systems to a stirred-tank system, utilizing Thermo Scientific™ HyPerforma™ Single-Use Bioreactors (S.U.B.s) and Cytodex™ 3 microcarriers (GE Healthcare). The study then demonstrates necessary processes for scaling up from the 50 L S.U.B. to the 250 L S.U.B. For each scale-up step from T-flasks through S.U.B.s, the cells were detached by trypsinization before going to the next step. To go from 50 L Single-Use Bioreactor. to 250 L Single-Use Bioreactor., the detached cells were collected by harvesting the contents of the bioreactor through a Thermo Scientific™ 3 L Harvestainer™ microcarrier separation system to separate the cells from the microcarriers. The collected cells were then added to the prepared 250 L Single-Use Bioreactor with new microcarriers.