The paper presents a methodology for assessing the phenomenon of fault-induced delayed voltage recovery (FIDVR) using data from phasor measurement units (PMU). The methodology allows the processing of time series of bus voltages in which indicators of voltage magnitude evolution performance are calculated and compared with technical criteria thresholds to evaluate the phenomenon, defining when, where, and with what magnitude FIDVR occurs in each analyzed time series. The methodology is validated using data from the Colombian power system operation obtained from PMUs installed in several substations that centralize information with the wide-area monitoring system (WAMS). The results show that this methodology can quantify and locate the FIDVR phenomenon in response to faults occurring in the national interconnected system using synchrophasor measurements. This methodology has been converted into the strategy of the National Dispatch Center of Colombia to monitor FIDVR and determine new reactive compensation requirements based on real data.