Gather the ingredients.
Place prime rib roast onto a large cutting board. Combine seasoning ingredients and slather all over roast. Make sure it is well coated.
Prepare grill for rotisserie cooking following the instructions in the grill manual.
Place the rib roast bone-side down. If you are using a boneless rib roast just place it on its side. Lift the roast from the ends and rotate it to find its approximate center.
Using a long, thin blade knife, cut through the center end to end.
Run the rotisserie skewer through the hole and loosely secure with the rotisserie forks.
Place roast on grill and adjust to center; then tighten the forks.
Remove from grill and preheat to a high temperature.
Place an aluminum drip pan under the space where the roast will sit. Add about a cup of water to the drip pan, if you intend to make gravy with the rendered juices.
Using heat-resistant gloves, return roast to grill.
Leave the grill on high for 20 minutes, then reduce the temperature to medium-low. Continue cooking until the internal temperature reaches 120 F(140 F for medium done).
Remove from grill and rotisserie rod, cover with aluminum foil, and allow to rest for 15 to 20 minutes.
Carve and place onto a platter.
Serve and enjoy!