Police got a call of shots fired at about 11:47 a.m. at a home in the 14200 block of Hillcrest Drive, according to Fontana police.
When officers arrived, they found the victims, two men in their 20s. Neighbors said they are brothers.
One man had a gunshot wound to the head and the other had stab wounds to the upper body.
Police said both were conscious and able to talk to investigators before being taken to a hospital. A juvenile in the home was not harmed, authorities said.
There was no word on a motive or possible suspects, but police said there was no forced entry at the home.
Anyone with information was urged to contact Fontana police at 909-350-7700.