The SPCA says the kittens were dehydrated and appeared lifeless when a woman walking nearby noticed them.
The cooler was left Monday, with a sign that read "free kittens."
B.C. SPCA general manager Lorie Chortyk says the kittens were only a few days old, some still had umbilical cords attached and their eyes hadn't opened yet.
Chortyk says the kittens certainly would have died if the woman hadn't called the SPCA right away.
The kittens are being cared for at the SPCA Animal Hospital in Vancouver and will be placed in foster homes for around-the-clock care when they're well enough to leave.