In vitro plant cell cultures are defi ned as a culture in aseptic conditions of any part of the plant body in a nutritive media. Cells, differentiated and undifferentiated (calli and suspended cells) tissues, and organs can be maintained in vitro .Some of the advantages of in vitro cultures are their development and maintenance in defi ned conditions (nutrients, light, humidity, temperature), independent from environmental infl uences (pests, diseases, extreme weather, geographical location, etc.), and manipulated by experienced operators in confi ned facilities.Since its development, in vitro plant cell cultures have been an essential tool for studying plant metabolism, and to micropropagate plant species, maintaining their genetic background. Also, they were helpful to analyze and optimize the production of plant secondary metabolites.Secondary metabolites productive processes are conducted, with a different degree of success, in undifferentiated cultures and in cultures of transformed organs. Several strategies were displayed in order to increase yields as manipulation of the plant growth regulator balance, addition of precursors, biotransformation, and immobilization.Also, as plant cells have a different behavior in liquid culture compared with microorganisms and mammal cells, bioreactor design was adapted to develop plant cell cultures.