Results of an acoustic study of root-initial /t th t'/ for eleven speakers of Witsuwit'en (Athabaskan) are presented. Values averaged across speaker means suggest that Witsuwit'en ejectives have a brief period of creaky voice and slow rise time at vowel onset relative to the voiceless unaspirated stops. However, there is considerable inter-speaker variation in VOT and f0 perturbation, with negligible correlation between these measures, contrary to the predictions of the ejective typologies proposed by Lindau (1984) and Kingston (1985). Results of a perception study indicate that the ejective-voiceless unaspirated contrast is more difficult than the other laryngeal contrasts even for native listeners. Implications of the Witsuwit'en data for the categorization of ejectives are discussed.