The potential for electrocution by undetected electrical feedback in power lines and measures for prevention were discussed. Two recent cases were described and others cases which were very similar were cited. In the first case, a 38 year old lineman in an aerial bucket was repairing a 13.2 kilovolt power line which was one of two servicing a residential area. A third line was present which serviced a store. The residential lines were deenergized, but not the store line. Feedback from the store line through the transformer inadvertently energized the line on which a splice was to be made. The lineman checked the line by touching it with pliers held in his gloved hand, but this method did not detect low voltage. At the time of electrocution the lines had not been grounded and he was not wearing lineman's gloves. The second case involved a 33 year old electrician who died of injuries due to falling from a 30 foot bucket when he contacted feedback energy from the ungrounded load side of a circuit. Recommendations arising from this study include proper training in electrical procedures, proper verification that power lines are deenergized before work is begun, checking for the possibility that feedback electrical energy is present, and use of proper work practices and protective equipment.