The one-alarm fire was reported at 7:35 a.m. at 448 Downen Place near Santa Clara Street, Hayward fire Capt. Thor Poulsen said.
Someone called 911 to say they saw their neighbor trying to put out a fire in their bedroom. Firefighters arrived and saw heavy smoke and flames coming from the home, Poulsen said.
The blaze was extinguished with 15 minutes of the firefighters' arrival, he said.
Four residents of the home got out safely, and a cat, four kittens and a pit bull were also rescued, according to Poulsen.
The fire was contained to the bedroom of the home. The cause of the blaze has not been determined, but two fire inspectors were at the scene this morning because "it's a little strange to have a fire break out in the bedroom," Poulsen said.