Simultaneous radar and photometric measurements of the mean energy of precipitating electrons have been made at Chatanika, Alaska, during a variety of auroral conditions. The radar measurements of the altitude profile of electron density were used to obtain the differential energy spectrum of the precipitating flux. Photometric measurements of 4278- and 6300-¿ emission intensities over the same region and time span were analyzed in terms of the mean energy parameter, as was previously described by Rees and Luckey (1974). The mean energy parameter values determined by the two techniques show good agreement, which tends to confirm quantitatively the theoretical predictions of Rees and Luckey. The energy parameter range measured was ~3--15 keV, and the auroral intensities ranged from about IBC I to IBC III (<1 to ~10 kR of 4278-¿ intensity).