They were found on a property in Co Leitrim. Many were puppies.
The ISPCA said they were mostly bichon frise crosses, King Charles cavaliers, and shih tzus.
ISPCA chief inspector Conor Dowling said the animals were in an “appalling condition”. Many had severe health problems.
“Their coats were also matted with sawdust, dog faeces, and mud and their legs were soaked in urine.”
Animal welfare inspectors described the woman who owned the land as somebody who kept and bred dogs without rehoming them or necessarily having the resources to care for them.
Leitrim county veterinary officer James Madden said the woman was breeding some of the animals, but it also appeared that she was taking in other abandoned animals at the property.
ISPCA officials said the dogs were rescued over five days and the operation was so large it had to be co-ordinated by five different groups.