Some of the kittens were recently removed from a property in Co Wicklow where the cats were breeding out of control.
The ISPCA is looking for forever homes for 91 cats and kittens.
The charity says it's extremely busy at a number of its care centres around the country due to the volume of animals it's looking after.
68 cats and kittens are available for rehoming at the National Animal Centre in Longford, there's 19 at the ISPCA's Donegal Animal Rehabilitation Centre, while there's four kittens at a rescue centre in Mallow, Co Cork.
All of the animals are fully vaccinated, neutered/spayed and litter-trained.
The ISPCA says that if anyone is thinking of adopting a cat or kitten to get in touch.
Their National Animal Centre in Keenagh, Co Longford is open to visitors Wednesdays to Sundays from 11:30am to 4pm.
The ISPCA is appealing for new homes for 68 #cats & #kittens at our National Animal Centre #Longford. A further 19 are available for rehoming at our #Donegal ARC & 4 kittens at our Equine Centre, #Mallow. Can you help?
Visit https://t.co/TBVEU5nWn3 #adopt #donate #CatsOfTwitter pic.twitter.com/RuAV1ToaGt— ISPCA (@ISPCA1) July 31, 2019