This review focuses on the performance of immobilized cell bioreactors utilizing a magnetic field. These reactors utilized immobilized cells on magnetic particles or beads as the solid phase. All published research papers dealing with the performance of immobilized cell bioreactors utilizing a magnetic field from the early 1960s to the present time were considered and analyzed. It was noted that many microorganisms such as Saccharomyces cerevisiae were immobilized on different supports in these reactors. These papers used the magnetic field for several purposes, mainly for the stabilization of magnetic particles to prevent their washout from the column while operating with relatively high substrate flow rates to enhance mass transfer processes. It was observed that most publications used an axial magnetic field. In addition, most of the magnetic particles were prepared by entrapment. Some comments are presented at the end of the review which show the gaps in this promising application.