Firefighter spokeswoman Pavlina Adamcova said the fire broke out after midnight Wednesday in the dilapidated two-story building, which had been slated to be demolished. The building near the city's main bus station collapsed before firefighters could enter.
Adamcova said eight people were found dead at the scene. Police spokeswoman Ivana Jezkova said investigators recovered one more body during the day.
The victims were not identified, but Czech public radio and television stations say they were probably homeless.
The building belonged to Czech Railways and was abandoned for a year. Adamcova says no nearby buildings were damaged.
Authorities continue to investigate.
Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.