The formation of gas bubbles injected into an insulating liquid was studied under the influence of a nonuniform electric field. The electrode configuration used consisted of a charged capillary opposite a grounded ring, and gas bubbles were formed at the capillary tip. The experimental part of the investigation afforded insight into the mechanism of bubble formation, which is influenced by the existence of corona discharge. Based on the balance of forces at bubble detachment, a theoretical model was developed to predict the variation in bubble sizes. The theory agrees closely with experimental results over a range of applied voltages where the corona discharges were absent.