Lynn Durnall, owner of Pinetrees Cattery near Cannock in Staffordshire, said 20 cats were in the facility at the time, the Staffordshire Newsletter reported. Two were being treated for smoke inhalation, and she said one seemed certain to survive.
"The only shreds of comfort I can take are that we weren't particularly busy and at least some of the cats are OK," she said.
The fire is believed to have been caused by an electrical problem, authorities said. Dermot Hogan, a fire official, said the wooden building was gutted by the blaze, The Daily Telegraph reported.
Phil McFarlane of the Staffordshire Fire and Rescue Service said some of the missing cats may have run off into nearby woods.
"From my 30 years experience, when any animal that is trapped by fire manages to escape, they tend to do so with immense vigor and tend to leave the scene," he said.