Theft of electricity is the criminal practice of stealing electrical power. It is a crime and is punishable by fines and/or incarceration. It belongs to the non-technical losses. According to the annual Emerging Markets Smart Grid: Outlook 2015 study by the Northeast Group, LLC, the world loses US$89.3 billion annually to electricity theft. The highest losses were in India ($16.2 billion), followed by Brazil ($10.5 billion) and Russia ($5.1 billion). Electrical power theft detection and control system is used to detect the consumer when they try to use the power illegally. Electricity theft happens when the customer uses energy meter tampering such as placing a magnet near to energy meter, disconnecting the neutral line and shorting the phase coil of the current transformer. To identify and control power theft here an intelligent system is introduced. It consists of two current transformers that are used to measure the actual load current and the other is to measure the turning back or neutral current. Those two current signals are fed to the microcontroller. The microcontroller will compare these two current signals. Depending on the comparison made by the microcontroller it concludes whether power is theft through bypassing the energy meter or not and a message will be sent to notify the authorized power vendor using GSM Hence the power vendor can easily identify the customer who is illegally consuming the power for that energy meter. Moreover, when there is an occurrence of theft the relay will disconnect the load from the supply. The GSM based power theft control system is developed. We used Proteus software to analyze and estimate what the hardware will look like. Mainly this system consists of microcontroller, energy meter, current transformers, LDR, relay, LCD and GSM module.