This experiment in aural speaker identification attempts to ascertain the relative contributions of fundamental frequency and formant frequencies. Speech samples were four voiced, whispered, and low-pass filtered isolated vowels produced by eight male speakers. Twelve listeners were asked to make speaker identification choices from these stimuli. Utterances were subjected to acoustic analyses, and the parameters extracted were related to speaker identification confusions by rank order correlation techniques. Results indicate that both fundamental frequency and formant frequencies contribute (approximately equally) to speaker identification judgments.