A New Kitten and an Old Cat
There can be a great relationship built between your existing pet cat and a new, playful kitten. Though this may happen over a period of time you need to be prepared for some possible stress in the beginning.
I am not here to scare you into deciding against it but the reality is that after several years of being king of the castle an older cat may be a bit territorial. Though cats that are confined to the indoors can benefit from a companion the best rule is have the introduction when both are younger.
When this is not possible convert to procedure. The general rule of thumb is that two cats of the same sex can create an environment of rivalry. To avoid this try your best to choose a cat of the opposite sex of your older cat. This will bring the need for a spay/neuter but the medical attributes are beneficial for both cats and this is always recommended.
Be sure that you have your new kitten checked by your family veterinarian before bringing him/her home. With a weak immunity you do not want to risk your kitten bringing a disease home to your older cat. Older cats begin experiencing weakened immune function as well so be weary of a stray kitten.
If possible you may bathe your kitten at a family member or friends house before returning home. This can help to neutralize their natural smell and prevent certain behavior’s from your older cat.
A mandatory isolation period may be required. In which time provide a separate litter box, food dish, and water bowl. The best circumstance would allow the kitten a private room. Though some kittens may be quite anxious to explore, this means of separation may help your older cat to adjust as well. If the kitten is fearful then do not force him/her to exit the room. Allow them to enter the living area on their own terms. Forcing an entrance will induce more seclusion and hiding.
The official introduction, face to face, should come a little later. Allow your older cat to explore the kittens belongings and get a scent. Then allow the kitten to do the same. Let the two meet for a few minutes at a time before allowing full time exposure. Doing the routine in this fashion will save you and your cats a lot of stress.