We put them in our dishwasher all the time and they're fine. Mine from 2004 and 2007 are still kicking, and we use them a lot. (My sons love using Disney Mugs for hot cocoa)
Great, thank you! We bought two from our trip last year - and two more for our Disneymoon this year so 4 mugs is too many for handwashing when you're already spoiled from a dishwasher. LOL