Preheat the oven to 400 degrees F.
Cut off the ends of the Brussels sprouts. If the Brussels sprouts are large, cut in half. If they are small, it is ok to leave them whole. If they are extra large, you can quarter them, must make sure they are all the same size.
Place sprouts in a medium bowl. Toss with olive oil and balsamic vinegar. Season with salt and pepper.
Pour Brussels sprouts on a large baking sheet, making sure they aren't touching and roast for 30 to 40 minutes or until sprouts are tender but crispy on the outside. Make sure you stir them a couple of times while they are roasting. Serve warm.