Analyses of errors in the natural speech of Dutch, German, and English have shown that involuntary rearrangements of phonemes (e.g., left hemisphere heft lemisphere) are more likely to occur when the two words involved in the error have the same phoneme before or after the phoneme on which the error occurred (e.g., /E/ in left hemisphere) [1, 2]. A study by Dell (1984) has revealed that phoneme repetition could also contribute to experimentally induced speech errors in English [3]. The present study explored the effect of repeated phonemes in Japanese speech errors by means of two errorinducing experiments. Analyses of subjects’ errors showed that a sequence of syllables that share the same phoneme was more error-prone than one with a variety of phonemes, suggesting that phoneme repetition could contribute to Japanese speech errors. These results are consistent with the view that the repeated phoneme effect is common to all speakers regardless of language.