In the present in vitro model, the authors intended to assess viability and functionality of hepatocytes encapsulated into alginate beads and submitted to a fluidized bed motion in a bioreactor. Human immortalized C3A line was chosen as cell model. Two controls consisting of (1) cells cultured on flasks and (2) cells encapsulated in alginate beads under static conditions were implemented. The cell functions studied were total protein, albumin, urea, and ammonia synthesis, as well as ammonia removal in the case of overdose. The comparison among the three cases studied showed that the three-dimensional structure of alginate offered a suitable environment for cell functions. In addition, the fluidized bed bioreactor enhanced the mass transfer and thus increased the amount of species released out of the beads, as compared with the static case. Ammonia detoxification only appeared reduced by encapsulation. The concept of a fluidized bed bioartificial liver was thus validated by this in vitro model, which indicated that cell functions could be efficiently retained. In addition, as far as urea and protein synthesis and release were concerned, the use of the MA cell line, in combination with encapsulation and fluidization technology, offered a real potentiality for the purpose of extracorporeal liver supply.