The document presents a study that develops an optimal load frequency control (LFC) method for two-area power systems using a harmony search (HS) algorithm to tune the parameters of a PI controller (Kp and Ki). The HS algorithm is used to minimize an objective function of integral absolute error (IAE) in order to enhance system performance regarding settling time, maximum deviation, and peak time. The two-area power system model and HS-PI controller design are implemented in MATLAB. Results show the HS-PI controller provides more robust performance compared to a particle swarm optimization-based PI controller under different load conditions.