Spermatozoa are male gametes that have an advantage in acting as gene transfer media (SMGT), because in transferring genetic material, sperm uses relatively natural vectors. This study was conducted to know sperm quality of Koi after short electroporation with different voltages using Gene Pulser. The study was conducted using a complete randomized design (RAL) with three (3) replications and five (5) treatments, namely: 10 V.cm-1 , 20 V.cm-1 , 30 V.cm-1 , 40 V.cm-1 , and 1 control. Electroporation was done with square wave, 1 ms duration of electroporation, 4 times of electroporation shocks with 0.1 s duration. The results showed that electroporation with different voltage levels significantly affected the motility and viability of sperm. Based on orthogonal polynomial analysis, it was known that the treatment affected motility and viability of sperm with a linear equation y =-0.9x + 5, 4 R² = 0.920 and r = 0.96 for motility and y =-11.26x + 91.61 R² = 0.823 and r = 0.91 for viability, meaning that the higher the level of electroporation the lower the viability and sperm motility produced. From the results of this study, it can be suggested that the electroporation of Koi sperm as a gene transfer medium should be performed at a voltage of 10 V.cm-1 .