Eighty-six dogs, including 23 puppies, were removed by ISPCA Inspectors from an unlicensed dog breeding establishment in Co Roscommon.
It followed a visit by an inspector and the county dog warden last Friday.
The dogs were being kept in "very poor conditions" and had only one person to care for them all.
Nineteen of the dogs were suffering from a variety of health issues - including mange, eye conditions and ear infections.
They are now receiving veterinary treatment, the ISPCA said.
A further 17 puppies were removed from a house on Thursday - where the owner had allowed his dogs to breed without consideration for the consequences.
All of the dogs will need to be vaccinated, neutered and microchipped before being re-homed.
Image: ISPCA
The ISPCA is appealing to the public for donations, after taking in over 100 dogs in just three days.
The dogs - including Shih Tzu’s, Cocker Spaniels, Jack Russell terriers, Pugs and French bulldogs - are currently being cared for at the ISPCA’s animal centres in Longford and Donegal.
Twenty-five of the dogs have been transferred to the Dogs Trust.
The ISPCA is asking the public to report their suspicions about unlicensed dog breeders to its National Animal Cruelty Helpline on 1890-515-515 or to their local authority.
Image: ISPCA
It is also asking pet owners to ensure that they get their dog neutered to avoid unwanted litters.
The 17 puppies removed from a private home were the result of the owner failing to get his dogs neutered, the ISPCA said.
Image: ISPCA
Senior ISPCA Inspector Kevin McGinley said: "The ISPCA is grateful to have secured the removal of all dogs from this unlicensed premises.
"With so many dogs in our care we are appealing to the public to support us financially with this challenge and by offering responsible homes for the pups and dogs."