Toss the Brussels sprouts with the oil, salt and pepper, place on a rimmed sheet pan and roast in the oven for 20 minutes.
Remove the pan from oven and pour the pomegranate juice and vinegar over the Brussels sprouts, stirring well to coat. Return the pan to the oven for another 15 minutes, stirring the Brussels sprouts halfway through baking.
Remove from the oven when the sprouts are tender and the pomegranate vinegar glaze has been absorbed. Toss with the pomegranate seeds and serve warm.