The RSPCA wants people to take better care of their pets during the school holidays after the number of strays it has taken in during the break tripled.
On average, two strays are brought into the Bristol home daily; this has now risen to six, with the holidays and neglectful owners blamed.
The charity says its home is "overrun" and all 190 spaces are now full.
Lyn Gilman, from the Bristol Dogs Home, said: "There are too many people who think their pet can fend for itself."
She added: "Others decide they simply don't want the dog anymore and just let it loose on the streets.
"Many people mistakenly think that the home just keeps animals for a fixed time and then puts them to sleep but this is not the case.
"The animals get the veterinary care that they need and stay as long as it takes to be rehoused."
Staff at the home are also asking pet owners to get their animals microchipped to ensure they can be swiftly returned if they are found as strays.