FORTUNE — Thousands of workplaces around the country play host to a parade of canine visitors on Friday, June 21, in honor of Take Your Dog to Work Day. But for some employees, dogs come to work every day.
At Google (GOOG), research scientist Elin Pedersen drives to work about twice a week with her Great Dane Leika, who she says keeps her from getting stuck on thorny problems.
“I walk her every other hour, just briefly, going out and around the block. That is really good for my brain,” Pedersen says. “I am way more productive when I have her with me.”
Other dog-friendly employers across the continent include Nestle Purina PetCare Co. in St. Louis, gaming firm Zynga (znga) in San Francisco, INVIVO in Toronto, and even Comedy Central’s The Daily Show with Jon Stewart. And many more companies allow dogs on the annual observation of Take Your Dog to Work Day, which has grown from just 300 participating companies in 1999 to thousands now, according to sponsor Pet Sitters International.
Researchers have found that having dogs in work environments can lead to better teamwork, boosted morale, lower stress, and higher employee retention.
“Dogs in the workplace can make a positive difference,” says Randolph T. Barker, a professor of management at the VCU School of Business, who has studied the effects of the presence of pets on worker stress levels. “The differences in perceived stress between days the dog was present and absent were significant. The employees as a whole had higher job satisfaction than industry norms.”
But before bringing dogs into the office, both employer and employee must take a few important steps. Employers should survey the workforce about allergies or phobias that would need to be accommodated. Employees should make sure their pets are well-trained and not aggressive around people or other animals. “We are the first to admit that this may not be a good fit for every workplace,” says Beth Stultz, marketing manager for Pet Sitters International.
Employers should set policies and parameters for areas where the dogs are permitted and establish expectations for dogs’ behavior. Pet owners should provide food, water, toys, and a bed for their animal and might consider using baby gates or bringing the dog to work on a weekend so they can become accustomed to the space.
Dog owners at Google realize they must shoulder the burden of avoiding accidents or a colleague being bothered by their pet. There’s a one-strike policy for messes or aggressive behavior. “It’s a privilege with a lot of responsibilities,” Pedersen says.
At Zynga, every dog owner registers her pet with the company and provides health records of up-to-date vaccinations. Employees can walk the dogs in a “wooftop” dog park or tie them up outside the cafeteria in a dog-friendly “barking lot.”
When senior producer Sora Bai adopted her dog Itsy, word went around the office that there was a new puppy, bringing visitors to Bai’s desk that she’d never met before. “She knows more people than I do,” Bai says about the dog, who has helped her owner become more social in the hallways and at the dog run. “I talk more to people than I knew previously because we have the dogs in common.”
So many dogs come to Zynga, whose corporate name comes from the founder’s dog, that meetings might include several canines roughhousing. “For new people, it’s a little weird because all of a sudden you’re hearing four dogs playing in the corner,” Bai says.
A recent study by researchers at Central Michigan University suggests that workplaces with dogs might also engage in higher levels of collaboration and ethical behavior. The 120 individuals who participated in the study scored higher overall on measures of trust, team cohesion, and intimacy when dogs were present.
“Pet presence may serve as a low-cost wellness intervention readily available to many organizations and may enhance organizational satisfaction and perceptions of support,” says VCU’s Barker. “Of course, it is important to have policies in place to ensure only friendly, clean, and well-behaved pets are present in the workplace.”