A new probe based on the measurement of the electrical capacitance has been developed to measure liquid holdup in columns equipped with structured packings. The main advantages of this new probe are that it is nonintrusive, it allows fast and online measurements, and it can be used for laboratory-scale columns as well as for industrial applications. The probe is designed to measure local liquid holdup and it can therefore be used to evaluate the presence of the liquid hold-up gradient inside each packing element in the column. Evaluation of the liquid hold-up gradient is helpful to identify locations inside the packing element where flooding begins and to suggest packing design modifications. The relation between electrical capacitance and liquid holdup closely follows the predictions obtained using simple electrical models. The experimental results obtained with the probe have enabled a simplified model to be tuned to predict capacity limits of columns equipped with structured packings.