The state estimator is a fundamental part of the overall monitoring and control systems for power grids. Up to date, in most cases state estimators data are supplied only from traditional supervisory control and data acquisition systems, which collects the real-time measurements from remote terminal units installed in substations. Nowadays, phasor measurement units technology provides more accurate and higher precision real-time measurements than those from remote terminal units. Additionally, phasor measurement units are able to provide both magnitude and phase angle of the measured voltages or currents. This paper reports on the implementation of a state estimation algorithm able to combine measurements obtained from remote terminal units with those from phasor measurement units. Effectiveness of the algorithm has been evaluated on two wellknown benchmark power systems.