Transfection of DNA into non adherent cells can be achieved by electropermeation. Previously published results, partially successful, were obtained using exponential decaying electric impulsions. However, one limitation of this technique has been the damaging effect of this type of impulsions resulting in poor cell recovery. We report hereby the electropermeation of human lymphoblastoid cell lines using a commercially available electropulsator delivering repeated, short, high voltage, square shaped, electric pulses. The parameters of transfection have been optimized using the "Lucifer Yellow Permeation Assay". With the optimum electric parameters, virtually all the cells were permeated and at least 70% survived the shocking conditions. Both transient expression and permanent integration and expression of DNA was observed.