The RSPCA rescued 2,621 animals in the first four months of 2008
RSPCA staff rescued 23% more abandoned pets in 2007 than in the previous year, the charity has said - and it warned the upward trend could continue.
The RSPCA says it was called on to save nearly 150,000 animals last year.
Many of these were farm animals and pets rescued during the summer floods, or birds injured by oil spills.
However, 7,347 rescued animals were abandoned pets, compared with 5,959 in 2006. The charity warned that abandoning pets was an offence.
Examples of dumped animals included a litter of kittens left in a dustbin bag, and a rabbit abandoned in a box in a crushing machine at a recycling centre.
Excuses given by owners who no longer wanted to look after their pets were said to have included: "My dog hurts my legs when she wags her tail," and "my cat doesn't match my new carpet."
Within the first four months of this year, 2,621 abandoned animals had been rescued, the charity said.
Tim Wass, chief officer of the RSPCA inspectorate, said: "From birds injured by oil spills to stranded cattle, and cats in road traffic accidents to dogs simply abandoned by their owners, the RSPCA was on hand last year to help all types of animals whatever the emergency.
"Last summer we deployed the biggest number of RSPCA staff for a generation to the rescue of farm animals, horses and other much-loved pets from the severe floods that swept the country."
But, he added: "Sadly we also noticed a rise in the number of animals callously abandoned.
"It is an offence to abandon any animal and there is never any excuse for doing so.
"If people have pets they cannot care for, for any reason, then help and advice is always available from the RSPCA."