In recent years, Chinese hamster ovary (CHO) production vessel volume has reached more than 1 000 L in Chinese biopharms, and 10 000 L in foreign big biopharms, such as Lonza and Genetech. In general, there are some steps seed bioreactor for seed expansion, which decreases the efficiency of production process. In this work, a perfusion-based process was developed to drastically increase the split ratio during the scale-up of CHO cell cultures. Fed-batch cultures were inoculated with cells propagated in either batch or perfusion cultures that grown in disposable Cellbags using the WAVE Bioreactor system. The higher cell concentration of 2 x 10(7) cells/mL with 95% viability allowed to increase the split ratio to about 1:50-1:100 for inoculum propagated in perfusion culture. The method described here could reduce the number of required expansion steps and eliminate two or three bioreactors. Disposable perfusion bioreactor with only a few liters working volume have the potential to directly inoculate volumes of up to 1 000 liters. This would allow to shorten process time in these bioreactors, which often are the bottleneck in plant throughput.