Roost site selection should be influenced, in part, by predator avoidance strategies. Prey species may use olfactory cues to assess predation risk. Our objective was to determine if southern flying squirrels (Glaucomys volans) use olfaction for assessing predation risk and selecting safe roosting sites. We tested the response of captive flying squirrels to several scents placed inside nest boxes. Squirrels spent significantly less time overnight in nest boxes scented with fox squirrel (Sciurus niger) fur, bobcat (Lynx rufus) fur, red fox (Vulpes vulpes) urine, raccoon (Procyon lotor) fur, king snake (Lampropeltis getula), and corn snake (Elaphe guttata) than unscented (control) boxes. Nest boxes with gray squirrel (S. carolinensis) fur, red fox urine, raccoon fur, and corn snake scent were selected as daytime roosting sites less than would be expected by chance. Southern flying squirrels are a major usurper of red-cockaded woodpecker (Picoides borealis) cavities and may reduce reproduction in this endangered bird. Our results indicate that predator odor may be an effective means of deterring flying squirrels from roost sites. If so, predator scent application could be utilized to reduce negative impacts of flying squirrels on red-cockaded woodpeckers. (WILDLIFE SOCIETY BULLETIN 34(1):144–149; 2006)