This document provides a review of using Ant Colony Optimization (ACO) technique to tune the parameters of a PID controller for an Automatic Voltage Regulator (AVR) system. ACO is inspired by how real ants find the shortest path between their nest and food sources. It has been applied to determine optimal proportional, integral and derivative gains for the PID controller in order to improve the dynamic performance of the AVR system and maintain the generator terminal voltage following disturbances. The document discusses ACO-PID controller design and compares results to traditional PID tuning through MATLAB simulation. A literature review is also presented covering previous research that has applied optimization techniques like ACO, PSO and GA to tune PID controllers for AVR systems.