The single phase prepaid kHh meter consists of energy metering and STS system, based on International standard : IEC 62055-31, 62055-41, IEC 62055-51. The energy metering measure line voltage, current and calculates active, reative apparent power, energy, power factor, and RMS voltage and current. There are two separate inputs to measure line, ground, and /or neutral current enabling the meter to detect tempering to continue operating. Develpoment of single phase based on needs of PLN, which is about 7 milion units kWh meter up to year 2014, especially for new customer. The energy metering subsystem is developed based on CS5464 cirrus logic IC that has been widely used around the word . The features of CS5464 as follows: Energy Linearity 0.1% of reading over 1000;1 dynamic range, One-chip functions: Voltage and current mesurement - active, reative,and apparent power/energy - RMS Voltage and current calculations- current fault and voltage sag detection- calibration-phase compensation- Temperature sensor - energy pulse outputs, meets accuracy spec for IEC,ANSI,& JIS, low power consumption, Tamper detection and correction. Additional features include system-level calibration, voltage sag ,and current fault detection, peak detection, phase compensation, and energy pulse outputs. The STS subsystem proposed is develop based on texas instrument MSP430 tm series that has ultra low power consumption. The features of STS (standard transfer specifikation) as follows: communication parameter: 9600, 8, N, 1 and ASCII data; command Parameter: Process Token,Authentication result, validation result, set initial key, set time, and set manufacturing code. The STS algorithm is complied with STS compliance test: STS_501_4_2, STS_501-5-2, and STS_501-6-2. The prototype has been developed, tested and verivied in electrical energy conversion research laboratory ITB Keywords: electronic kWh meter, prepaid system, single phase, STS protocol.