A pulsed HF chemical laser utilizing the chain reaction between H2and F2has been operated with electric discharge initiation. A uniform transverse discharge is made possible through the use of spark preionization. For the mixture 1:1:10:0.06 (F2:H2:He:O2) at 120 Torr total pressure an output energy 1.01 times the electrical input has been achieved. The corresponding chemical efficiency was ∼1.0%. A tradeoff is observed between electrical efficiency and chemical efficiency with the maximum chemical efficiency of 2% being achieved at an electrical efficiency of 25%. Even higher electrical efficiencies are expected with further device optimization.