This chapter explores the use of bioreactors for cell multiplication in cultured meat product development. The chapter begins by first providing an overview of the principles and structure of a bioreactor, which is followed by a breakdown of bioreactor operation modes: batch cultivation, fed-batch cultivation and continuous cultivation. The chapter also highlights the important bioprocess parameters that need to be considered when creating a stem cell niche in a bioreactor, such as temperature, oxygen, pH level, lactic acid and culture mixing. The chapter considers cultivation anchorage-dependent cells in stirred tank bioreactors, the scale-up of a bioprocess in bioreactors and also highlights areas which could help reduce cost and optimise processing within bioreactors.