This study describes the development work to shorten the monoclonal antibody (mAb) production time in CHO cell cultures from 14 days to 8 days without impacting mAb titer or product quality. The proposed process increases cell inoculation densities up to 25x higher than a typical seeding density in the final production bioreactor, with the implementation of an ATF perfusion system in the N-1 stage. Similar antibody titer and N-glycosylation profiles were reached in 8 days using the 25x seed condition, as in 14 days using the 1x seed condition. Acidic variants in the 25x seed condition were 12-20% lower than the 1x seed condition. These results indicate that an accelerated 8-day antibody production process utilizing a 25x seeding strategy has the potential of achieving similar product quality and titer as the 1x seeding condition in a 14-day production process. (c) 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:829-832, 2013