Objective:To estimate electroporation(EP) influence on malignant and normal cells.Methods: Two cell lines including human malignant melanoma(Me-43) and normal human gingival fibroblast(HCFs) were used.EP parameters were the following:230,1000,1 730,2 300 V/cm;30 μ s by 3 impulses for every case.The viability of cells after EP was estimated by MTT assay. The ullrastructural analysis was observed by transmission electron microscope(Zeiss EM 900). Results:In the current study we observed the intracellular effect following EP on Me-43 and HGF cells.At the conditions applied,we did not observe any significant damage of mitochondrial activity in both cell lines treated by EP.Conversely,we showed that EP in some conditions can stimulate cells to proliferation.Some changes induced by EP were only visible in electron microscopy.In fibroblast cells we observed significant changes in lower parameters of EP(230 and 1 000 V/cm).After applying higher electric field intensities(2 300 V/cm) we detected many vacuoles,myelin-like bodies and swallowed endoplasmic reticulum.In melanoma cells such strong pathological modifications after EP were not observed,in comparison with control cells. The ultrastructure of both treated cell lines was changed according to the applied parameters of EP.Conclusions:We can claim that EP conditions are cell line dependent.In terms of the intracellular morphology,human fibroblasts are more sensitive to electric field as compared with melanoma cells.Optimal conditions should be determined for each cell line.Summarizing our study,we can conclude that EP is not an invasive method for human normal and malignant cells. This technique can be safely applied in chemotherapy for delivering drugs into tumor cells. Objective: To estimate electroporation (EP) influence on malignant and normal cells. Methods: Two cell lines including human malignant melanoma (Me-43) and normal human gingival fibroblast (HCFs) were used. EP parameters were the following: 230, 1000, 1 730,2 300 V / cm; 30 μs by 3 impulses for every case. The viability of cells after EP was estimated by MTT assay. The ullrastructural analysis was observed by transmission electron microscope (Zeiss EM 900). Results: In the current study we observed the intracellular effect following EP on Me-43 and HGF cells. At the conditions applied, we did not observe any significant damage of mitochondrial activity in both cell lines treated by EP. Conversely, we showed that EP in some conditions can stimulate cells to proliferation .ome changes induced by EP were only visible in electron microscopy.In fibroblast cells we seen significant changes in lower parameters of EP (230 and 1000 V / cm). After applying higher electric field intensities (2 300 V / cm) we detect ed many vacuoles, myelin-like bodies and swallowed endoplasmic reticulum. In melanoma cells such strong pathological modifications after EP were not observed, in comparison with control cells. The ultrastructure of both treated cell lines was changed according to the applied parameters of EP. Conclusions : We can claim that terms are cell line dependent. Terms of the intracellular morphology, human fibroblasts are more sensitive to electric field as compared with melanoma cells. Optimal conditions should be determined for each cell line. that EP is not an invasive method for human normal and malignant cells. This technique can be safely applied in chemotherapy for delivering drugs into tumor cells.