Plant cell culture is seen as an alternative source to whole plants for the production of useful compounds, such as dyes, pharmaceuticals, perfumes and insecticides. Despite intensive research for the last 30 years, only a few products have reached commercial production in bioreactors, and the number is far less than those commercialized for bacterial and animal cells. Several biological challenges including slow cell growth, low productivity, compartmentation, metabolite channelling and poor metabolite secretion have hampered the realization of commercialization of plant cell products. Other engineering and technological problems include cell aggregation, plant cell shear sensitivity, foaming and lack of automation. Several strategies are being explored to improve productivity including medium optimization and cultural conditions, and the understanding of biochemical and signal transduction pathways. In plant cell culture process development, there is a great need to explore a more rational approach through metabolic and genetic engineering by making use of advanced technologies in genomic, transcriptomic, proteomic and metabolomic analyses. These should be integrated with developments in bioprocess and systems engineering.