Seven were taken to hospital, two in a serious condition, after the fire at Standon House Care Home in Tamworth, Staffordshire, on Saturday night.
The fire was accidental, caused by "poorly discarded smoking materials," Staffordshire Fire and Rescue Service said.
All residents were moved to alternative accommodation, police said.
About 20 firefighters were sent to the property, which suffered "very considerable" damage, the ambulance service said.
The ambulance service said 16 residents were rehoused within adjacent flats, with a further two people taken by ambulance to other care homes.
Emergency services were called to the home in Ashby Road at 23:00 BST and "fortunately, firefighters and staff were able to bring all of the residents out of the building," the ambulance service said.
Six people, including the two in a serious condition, were taken to Good Hope Hospital in Sutton Coldfield with a further patient taken to Queen's Hospital in Burton.
The seven were taken to the hospitals to be "assessed after smoke inhalation," Staffordshire Police said.
Insp Beverley Rounds, of Staffordshire Police, said: "We've had a number of calls from people living nearby and we want to thank them for their vigilance and reassure them the residents have been evacuated."
At least 25 residents were evacuated from a care home after a large fire tore through the property.