The distribution of electrical energy through medium voltage (20 kV) distribution networks often experiences energy losses, both technical and non-technical. This research aims to analyze the amount of energy loss and technical loss on the Kakung feeder at PT PLN (Persero) UP3 Lenteng Agung. The methods used in this study include the collection of primary and secondary data, calculations of current, voltage, and power at specific points in the network. Additionally, to validate the manual calculation results, a distribution system simulation was performed using ETAP software to obtain computerized technical losses. Furthermore, voltage drop and power loss analyses were conducted to determine the efficiency of energy distribution. The calculation results indicate that the total energy loss on this feeder reaches 4.065.086,76 kWH or 7,83% of the total energy distributed, while the technical loss from manual calculations amounts to amounting to 4.065.086,76 kWH (7,83%). By understanding the magnitude and causes of these losses, it is hoped that it can serve as a basis for planning improvements to the distribution system to make it more efficient and reliable.