The owners thought they had two females, and that looking after them would be a simple process.
But they were wrong – they had one of each sex, which reproduced faster than the owners could react.
And when Worthing Guinea Pig Rescue was called in to help there were already 160 animals running around the garden.
Jenny Dorney, from the centre, said: “The owner had looked after them incredibly well, especially given the circumstances.
“I don’t think he intended to end up with 160 guinea pigs – but he did a fantastic job.
“They were well fed, and had a good amount of space in his back garden. However, I do wish he had sought help earlier.”
An animal rescue team was called out to the couple’s home, in Gosport, but due to the number of guinea pigs, Worthing Guinea Pig Rescue was called out to assist, as they were the only ones with enough space for such a large number.
Jenny added: “We will always come and help and give advice before it gets out of hand like this situation. “Once we confirmed the sex of all 160, we separated off the males.
“Some of the animals needed treatment for mites and fungal but all have been fairly well treated.”
The guinea pigs are being distributed to rescue homes across the country by Piggy Bank UK, where they will be found a loving home to go to.
Ms Dorney added: “I have got 17 boys and 20 girls – plus their babies – waiting to be picked up over the coming days.
“All of the girls are still pregnant, so this family of theirs is going to get even bigger.”
It is expected that the total number of guinea pigs will rise to 194.
Ms Dorney was keen to stress that the previous owner had looked after the large family very well, but that it had simply become too much for him to carry on.
Suzanne Norbury from the RSPCA said: “We would recommend people neuter their animals at the earliest opportunity to avoid finding themselves in a similar situation, and to improve the welfare of the animals.
“In some circumstances we help people who are struggling to cover the cost of neutering.”