This paper presents an automatic monitoring algorithm of power quality (PQ) voltage events. The proposed algorithm is based on using the recursive self-tuning least squares technique for the estimation of the magnitude, frequency and phase of the PQ voltage signal components. The monitoring process is divided into two stages: detection stage and classification stage. The PQ voltage events detected and classified are interruption, voltage sags, undervoltage, overvoltage, and voltage swells. Generated signals using parametric equations and simulated signals using electromagnetic transient program (EMTP-ATP) is used to test the validity and efficiency of the proposed practical method for automatic monitoring of PQ voltage events. Event inception and end as well as duration are estimated in the detection phase. The results obtained show the very high accuracy of the proposed method