Electric field pulses used for cell manipulation can cause irreversible cell damage. The mechanisms of the processes leading to such cell damage are very complicated. Our work demonstrated that exponential electric pulses with intensity of 2-7.5 kV/cm and duration of 5.2 ms were able to initiate peroxidation of fatty acid emulsions, liposomal membranes, red blood and Ehrlich ascite tumor cells. Electric pulses-induced peroxidation of erythrocyte membranes was followed by hemolysis. The electric treatment caused damage of E. coli membrane lipids which was accompanied by decreased cell survival. All these effects depended on field intensity. A relatively good correlation between pulse-induced peroxidation of erythrocyte membranes and hemolysis was observed. These results suggest that free radical mediated processes as lipid peroxidation and/or lipid degradation or fragmentation may be possible causes for electric pulses-induced irreversible cell damage.