A bioreactor for perfusion culture of suspension cells has an inverselyconical tank which includes a cell culture zone and a cell settling zone disposed annularly relative to the cell culture zone in the upper region of the tank. Thecell settling zone is adjacent to the conical walls of the tank and has a numberof frustoconical lamellar elements. The two zones are separated with a partitionwhich allows the zones to communicate only below the partition. Cell culture medium supplied to the culture zone overflows at the top of the settling zone after having passed through the settling zone between the lamellar elements. Due to the conical shape of the tank and the resulting shape of the settling zone, passages of upwardly increasing cross section are created in the settling zone thus enabling the settling of live cells in the settling zone and their return to the culture zone while the spent medium overflows. The design is relatively easy to scale up.
