Bat gates are installed at the entrances of abandoned mines to protect bat habitat and ensure human safety; however, the response of bats to gates has received little study. Using mist nets and video surveys, we compared use of abandoned mines in northern Idaho by bats (species, entries, and behavior), before and after installation of bat gates, with bat use at ungated reference mines. The number of bat species using mines and the number of individual bats entering mines declined significantly at mines where gates were installed, but not at ungated mines. In addition, 3 of 7 behaviors recorded (entry looping, flying in front, and entry retreating) changed noticeably in frequency of occurrence at experimental mines after being gated, but these changes were not statistically significant. Our data suggest that, in the short-term, bat gates decreased the use of mines by bats and changed their behavior at the abandoned mines we studied. However, our results should be viewed cautiously, given our small sample sizes.