This paper is designed to provide an introduction to the major directions in the use of electromagnetic fields (EMFs) of various types, amplitudes, frequencies, waveforms, and treatment times in microbial biotechnology. An attempt is made to compare critically some recently reported results and to outline the most promising areas for future research. Theory is mentioned when necessary, but the main emphasis has been placed on practical applications. Selected examples of relevance to biotechnology are discussed with respect to their advantages and drawbacks compared with conventional methods. The main advantage of the strong electric field pulse techniques such as electroporation and electrofusion is that, in many cases, they are more easily controlled and more effective than the classic techniques. If cell inactivation is desired, non-thermal killing by strong pulses or fast thermal sterilization by means of ohmic heating can be achieved. However, if cell viability must be preserved, problems such as adverse effects of toxic electrolytic products or a significant medium temperature increase can arise. Constant and pulsing magnetic fields and direct and alternating electric currents might be applied to regulate (stimulate or inhibit) cell proliferation or monitor cell growth and various other metabolic activities. A number of specific cell-independent factors can act synergistically with an external EMF, thus strongly modifying its effect. Therefore, highly efficient integrated processes such as polymer- supported electrofusion, electrodialysis culture, and bioelectrochemical conversions could be successfully operated. However, especially if large-scale processes are considered, economic reasons, scale-up difficulties, and subjective factors still limit a wider application of EMFs. The design of more efficient and cost-effective exposure conditions and the development of novel integrated bioelectro-processes are the major challenges in increasing the use and benefit of EMFs in biotechnology.