Yes, I lost two bottles. And I have NO IDEA where they went. Usually you can peg where you've lost something as large as a bottle - left it at a restaurant, in the rental car, at someone else's house, you get the drift. It's almost like leaving your purse behind - you certainly go back to get that. And it's not a cheap pair of bottles that we lost - they are like $9 each (CRAZY if you ask me). SO we are down to one lonely bottle, plus the two that spit back when you use them, and I coughed up another $9 to purchase one more bottle in the hopes that our sweet lovely almost 11 months old will take to a sippy cup. Those are much cheaper to lose...trust me, I know.