Speech production studies have shown that the phonological form of a word is made up of phonemic segments in stress-timed languages (e.g., Dutch) and of syllables in syllable timed languages (e.g., Chinese). To clarify the functional unit of mora-timed languages, the authors asked native Japanese speakers to perform an implicit priming task (A. S. Meyer, 1990, 1991). In Experiment 1, participants could speed up their production latencies when initial consonant and vowel (CV) of a target word were known in advance but failed to do so when the vowel was unknown. In Experiment 2, prior knowledge of the consonant and glide (Cj) produced no significant priming effect. However, in Experiment 3, significant effects were found for the consonant-vowel coupled with a nasal coda (CVN) and the consonant with a diphthong (CVV), compared with the consonant-vowel alone (CV). These results suggest that the implicit priming effects for Japanese are closely related to the CV-C and CV-V structure, called the mora. The authors discuss cross-linguistic differences in the phonological representation involved in phonological encoding, within current theories of word production.