The influence of voiced and vo iceless consonants on the Fo of the stressed vowel in words with different tonal accents is studied. Peak Fo of the vowel is circa 15 Hz lower after voiced than after unvoiced consonants; the influence of the preceding consonant is, however, not confined to the beginning of the vowel but still present near its end. The interval from vowel onset to Fo peak increases circa 25 msec when the preceding consonant is changed from voiceless to voiced. When Fo curves for long and short vowels are compared the Fo peak is found to remain constant relative to the nearest boundary of the vowel. The variations are discussed in relation to the mechanisms which cause them to occur and to their role in the speech communication process.