Pets Unlimited was founded in 1947 by a group of citizens concerned about the welfare of San Francisco's stray animals. From a temporary shelter, they began rescuing dogs from the city pound and finding homes for them.

Over the years, the organization grew, and a veterinary hospital/shelter was purchased on Sacramento Street. It was here that the Pets Unlimited veterinary hospital began to serve the community's pets as well as their own shelter animals. The hospital income was used to expand the shelter and launch innovative charity, community and education programs.

In the mid-seventies Pets Unlimited moved to its present location on Fillmore Street. By 1989, the hospital expanded to a 24-hour emergency facility to meet the growing needs of the community. Over the years the scope of programs and services has grown substantially.

Pets Unlimited now offers complete medical care, extended shelter services, a foster family program, volunteer opportunities and community educational services, both on and off-site. In 2007, 179 cats and 77 dogs were adopted into new homes through the Pets Unlimited Adoption Center.

Since inception, the organization has been instrumental in saving the lives of more than 250,000 animals. By providing 24-hour veterinary care, community education and innovative adoption programs, Pets Unlimited has earned the reputation as the premier provider of comprehensive and humane animal treatment in the Bay Area.