Officials with Sun Prairie Apartments told the Des Moines Register that the affected residents will be placed in open units elsewhere in the complex.
The fire was contained to one building at the complex. Fire Chief Don Cox says the fire that broke out about 3:30 p.m. Saturday destroyed much of the third floor and roof on the north side of the building.
KCCI-TV reports a total of 36 units were damaged.
Fire officials estimate the fire caused $1 million in damage to the building and residents' belongings.