The fire started about 1:50 a.m., at the Langhorne Rehabilitation Nursing Center, in the 300 block of Manor Avenue in Langhorne.
Officials quickly moved residents out of the wing where the fire began, to other areas of the building that were free of smoke and flames.
Five residents were taken to the hospital for observation and treatment of smoke inhalation. All are doing fine, and two of the residents were returned to the nursing center.
Ten residents have been temporarily moved to other nearby nursing centers due to water damage. However, those residents are expected to return to the center no later than Wednesday.
There is no word yet on what caused the fire.