RSPCA Cymru is calling for a ban on keeping primates as pets, saying hundreds may be "suffering behind closed doors".
The animal welfare charity hopes Wales will join 15 European countries which have implemented a ban.
Last year, it received more calls about primates in Wales than in any of the previous 11 years.
RSPCA's senior scientific officer, Ros Clubb said: "All primates, hand-reared or not, are wild animals.
"It doesn't matter how well intentioned the owner is, primates are not suitable pets."
"We fear there are hundreds more that are suffering behind closed doors because people do not know how to look after these animals properly."
It is estimated that there are around 120 privately-kept primates in Wales, with marmosets, capuchins and squirrel monkeys being the most common.
In a survey, RSPCA Cymru found that 72% of those polled in Wales support a ban of keeping primates as pets.
Former Assembly Member Lorraine Barrett re-homed a monkey from a pet shop in the 1980s after feeling "desperately sorry for him."
"The minute I walked in the house with the monkey I realised how out of my depth I was," she said.
"One time he was on the top of the cupboard and jumped on my son's head. I went to grab him and he bit me all around my arm. We were all just screaming."
"The only advice people need is that primates should never be kept as pets."