We have an 11 week old Yorkie who we have had for just over a week.  Lovely temperament showing already and quite well behaved.  I would like to introduce the pup to my sister's 3 year old Yorkie as she often visits with him and we want them to get on longer term in case either of us wants the other to care for the dogs together (if have to be away, in hospital, etc.).  My sisters dog does get on quite well with other dogs outdoors and was good pals with my old dog who was 11 years old.  We tried to introduce them yesterday, but it is clear my sisters dog is going to be jealous and he growled at the pup, and curled his lip! 

Any advice on how to move forward on this would be much appreciated!  Many thanks.

It's quite normal for an adult to growl at a puppy. He's just telling the puppy to mind his manners. If you have a cage you can let them get to know each other without the puppy being able to bother the older dog. If you don't, don't worry. Let them be together under supervision but give the older dog a way to get away from the pup (some adult males actually seem frightened of small puppies). Don't intervene if the older dog growls at the pup - as I said its normal. Don't worry either if the puppy sqeals when the older dog tells him off. The pup is only saying 'OK, I've got the message' and in all probability no contact has been made at all. Just be there in the very unlikely event that the older dog attacks the puppy in a serious way. IF you and your sister are relaxed about things the two will soon be the best of friends.

I would introduce the new puppy outside in neutral ground. Let them introduce each other under supervision. Then try to play with them with a ball or whatever they usually would play with. The older dog will accept the younger dog much easier that way. I will like to add that I always keep an eye on my older and youngest dog when playing.

Good idea about neutral ground.  We plan to walk the dogs together once the puppy is fully innoculated and can go out.

Many thanks for your advice.  We do have a cage and have kept the pup in it while the older dog investigates him there.  The older dog has been kept on a lead though and I am advised it is best to let him off and the lead can make him feel aggressive.  The pup is dying to get at the other dog and have a good play!  It is early days and I think your comments about our staying calm are good too!