Firefighters took a man out of the building and across the street where they tried to resuscitate him, but he was already gone. His identity has not been released.
At least six people were transported to the hospital, suffering from burns and smoke inhalation. Among the injured were a 40-year-old man and a 36-year-old woman, who are being treated for burns.
RAW VIDEO: Mission fire from ground level
The fire broke out around 6:30 p.m. on Wednesday. It destroyed a three-story building at 22nd and Mission streets. There were 125 firefighters that responded to the scene and after a while, they said they had to take a defensive position and let the building burn. A large section of the roof collapsed around 10 p.m.
PHOTOS: Crews battle massive fire in SF's Mission District
Thousands of gallons of water were pumped onto the fire and some minor flooding started to occur on the streets, due to the amount of water trying to go down the drains.
Witnesses said they saw people escaping from the building on fire escapes, coughing and suffering from smoke inhalation.
During the fire, there was a lot of panic and chaos. A 5-year-old girl was lost and later found, a boy and his dog had to be rescued, one tenant said he didn't even know the building was on fire until he looked out the window and saw the firefighters. Some escaping down the fire escapes couldn't make it to the ground because the street signs were blocking them. Firefighters then used a ladder to get those people down.
The fire created a huge cloud of smoke that was blowing across Highway 101 and could be smelled for miles.
The mixed-use building has businesses and offices on the first and second floor, and the third floor is mostly residential.
Mission Local, a San Francisco blog, reported that their office is in the building that caught fire.
Everyone in ML staff is OK and reporting on scene. Unclear how many injuries there are in bldg. More updates coming: http://t.co/4IqOM9atP9— Mission Local (@MLNow) January 29, 2015
The building looks like it will be a complete loss. Fire crews managed to save newly built condos next door.
At least 40 people were displaced by the fire and a number of nearby buildings were also evacuated. Some evacuees said there was no time to grab belongings - they just had to get out.
News crews and onlookers being moved back as for continues to creep toward Mission corner from 22 side pic.twitter.com/Jujtavt5s2— Mission Local (@MLNow) January 29, 2015
Resident Ricardo Cedeno said he was coming home from work when he saw his building on fire. He said his mother and stepfather were inside their home and escaped the fire, which started near their unit.
Cedeno said his stepfather was "washing something in the kitchen and then he had to go to the bathroom. Two minutes later when he was coming back, he just watched the flames coming out from one of the closets. Everything just happened just like in the blink of an eye."
An evacuation center was opened at San Francisco City College at 22nd and Bartlett streets. The American Red Cross is helping everyone it can.
"First making sure they're safe and comfortable, if they have any medical needs, perhaps if they're missing medications, we'll get those replaced and then we'll make sure they have a place to stay," Woody Baker-Cohn from the American Red Cross said.
The Red Cross says the best thing you can do is by donating money. To help victims of the Mission District fire, donations can be sent to the San Francisco chapter of the Red Cross.