1.  All the appropriate registration forms. 
 
2.  Proof of current vaccinations, parasite control, and physical exam record.
 
3.  Your pet's medications, if on any. 
 
4.  Your pet's food, especially if on a special diet.
 
5.  A leash or carrier during check-in and check-out, plus any personal items to make your pet's stay enjoyable.