Gas multiplication factors were measured in a proportional counter filled with high-purity ethylene in the pressure range 10-40 Torr. The multiplication factors were measured as a function of the reduced electric field S(a). The results show that, within the range of the high values of reduced electric field applied in this work (2648 < or = S(a) < or = 6455 V cm(-1) Torr(-1)), the reduced first Townsend coefficient alpha/P for ethylene may still be considered a function of S(a) alone. Good agreement was found with a model proposed by Akande.