1. We collected data on the wing temperature of flying bats using infrared thermal imaging to assess the thermoregulatory function of wing membranes. 2. Thermographic images of two Egyptian Fruit Bats, Rousettus aegyptiacus were captured as they flew along a 12 m length of corridor. 3. Body temperature was measured before the first flight and immediately after flight sequences using a rectal thermister probe. 4. Temperatures across the wing ranged from 34°C near the forearm muscle mass, to less than 24°C at the trailing edge (mean ambient temperature 23°C). The majority of the wing was 1-2°C above ambient temperature. 5. We found small, but significant changes in body temperature during flight. These changes did not correlate with changes in wing temperature.