A small colony of little brown bats Myotis lucifugus was observed feeding on mosquitoes (Culicidae) inside a barn near Fairbanks, Alaska in June 2000. Observations were made visually and with a bat detector. All capture attempts were associated with feeding buzzes, indicating that the bats used echolocation to detect and track the insects, although the light was bright and the insects were easily seen by us. The capture efficiency of the bats was 92% (n = 100). The insects did not show any defensive behaviour in response to approaching bats.