Five experiments indicated that the sheep ked MELOPHAGUS OVINUS (L.), can transmit bluetongue virus (BTV) in sheep. It was not determined whether these were mechanical or biological transmissions, although the results suggested mechanical transmission. Sheep keds were manually transferred from a BTV-host sheep to 18 susceptible test sheep. Of these, 10 were positive (5 with mild reactions), 6 questionable, and 2 negative for BTV. Three of the mildly reacting sheep and 3 of the questionable sheep had highly intensified reactions on challenge inoculation. Five of the positive sheep were immune on challenge inoculation. Blood from 2 positive reactors was subpassaged into susceptible sheep, which reacted with typical disease signs.