This work describes the percentage cell lysis produced by exponentially decaying electric field pulses of varying amplitudes and time constants. Three different cell types were examined: murine spleenocytes, hybridomas, and human natural killer. Cells were cultured and separate samples examined at 24 hours and 48 hours. Two sets of experiments were performed for each cell type. At 0.3 kV, the spleenocytes exhibited a mortality of roughly 50% twenty-four hours after exposure to the pulse; while at forty-eight hours the spleenocyte cell count had reduced to roughly 25% viable cells. All other cell types showed mortality consistently in excess of 80% at field pulse strengths of about 0.3 V/m.