When listeners attempted to tap in synchrony with a target phoneme in a repeating phrase or sentence (e.g., ``Most Wisconsin winters are cold.''), taps to syllable-initial phonemes were accurate, whereas taps to syllable-final phonemes were early. These results indicate that the apparent occurrence of speech sounds depends upon syllabification, and that the synchronous phoneme-tapping task can be used for investigating syllabic structure. The tapping paradigm was used to examine a topic of current interest---the syllabic assignment of intervocalic consonants. The stimuli were six minimal-contrast pairs of bisyllabic CVCVC words differing only in their first vowels, having either a tense V1 (as in ``tunic'') or a lax V1 (as in ``tonic''). Tense-V1 and lax-V1 words were presented to separate groups of 24 listeners who provided a sequence of 15 taps to each target phoneme in the repeated words. Intervocalic consonants (IVCs) following tense vowels elicited accurate tapping, indicating their treatment as second-syllable onsets, whereas taps to IVCs following lax vowels were early, indicating their treatment as first-syllable codas. These results are consistent with linguistic theory and explicit judgments of syllabification [see Trieman and Danis, J. Mem. Lang. 27, 87--104 (1988)].