We have measured the temperature of a nanocrystalline graphite/carbon nanotube field emitter film as a function of emission current in the range from 1 to 200 mu A. Theoretical considerations predict that cooling takes place from these emitters if the electron emission is governed by resonant tunneling. Resonant tunneling manifests itself by a saturation behavior in the I-V curve. Maximum cooling should take place near the saturation region. A thermally insulating test system was configured capable of measuring temperature changes in the millikelvin range. For the test sample, at an emission current of about 10 mu A, which is the current where saturation is observed, a reduction in the temperature of about 0.01 degrees C is obtained. The reduction in temperature is attributed to cooling. (C) 2008 American Vacuum Society.