Biden says the GOP ticket has backtracked on issues, ranging from a GOP budget he says would slash Medicare to a planned U.S. troop withdrawal from Afghanistan in 2014.
Biden said Romney and Ryan "are counting on the American people to have an overwhelming case of amnesia."
President Barack Obama has ridiculed Romney's apparent flip-flops as "Romnesia," which a boisterous crowd of 1,500 repeated.
Biden began his speech by praising Senate candidate and former Virginia governor Tim Kaine, then adding "I'm a big Tom Kaine fan."
Kaine responded through his Twitter account: "Thanks to the VPOTUS for the shout out today. I love Jay Biden!"
Romney spokesman Ryan Williams says Biden forgot Kaine's name "and he wants voters to forget about President Obama's failed economic policies."
