The number of animals abandoned in England and Wales in 2008 rose by 57% compared with the previous year, according to the RSPCA.
The charity fears that pets are becoming the latest victims of the credit crunch as owners struggle to pay for food, vets' bills and insurance.
The RSPCA's Tim Wass said: "It is an offence to abandon any animal and there is never any excuse for doing so."
The increase in workload comes as the charity warns of possible job cuts.
The RSPCA says an average of more than 30 animals were dumped every day last year across England and Wales.
It dealt with a total of 11,586 abandoned animals in 2008, compared to 7,347 in 2007.
The number of abandoned cats rose by 50% last year, while dogs increased by nearly a third.
The RSPCA is concerned that the trend will continue as a further 1,432 animals were abandoned in the first two months of 2009.
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