Orb is the early 7-2 favourite for the Kentucky Derby, with undefeated Verrazano the second choice in a full field of 20 horses.

The Shug McGaughey-trained Orb will start from barrier 16, a gate that has produced four winners, most recently Animal Kingdom two years ago.

McGaughey is in racing's Hall of Fame, but the 62-year-old trainer has yet to win the Derby in six previous tries.

Verrazano drew gate 14 and is 4-1 for the famous race at Churchill Downs on Saturday (Sunday AEST).

The colt is one of five starters for trainer Todd Pletcher.

Santa Anita Derby winner Goldencents is the third choice at 5-1 and will start from barrier right. He is trained by Doug O'Neill, who won last year with I'll Have Another.

Another Pletcher horse, Revolutionary, is the fourth choice at 10-1.