Vowel matching and identification experiments were carried out to investigate the perceptual contribution of harmonics in the first formant region of synthetic front vowels. In the first experiment, listeners selected the best phonetic match from anF1 continuum, for reference stimuli in which a band of two to five adjacent harmonics of equal intensity replaced theF1 peak;F1 values of best matches were near the frequency of the highest frequency harmonic in the band. Attenuation of the highest harmonic in the band resulted in lowerF1 matches. Attenuation of the lowest harmonic had no significant effects, except in the case of a 2‐harmonic band, where higherF1 matches were selected. A second experiment investigated the shifts in matchedF1 resulting from an intensity increment to either one of a pair of harmonics in theF1 region. These shifts were relatively invariant over different harmonic frequencies and proportional to the fundamental frequency. A third experiment used a vowel identification task to determine phoneme boundaries on anF1 continuum. These boundaries were not substantially altered when the stimuli comprised only the two most prominent harmonics in theF1 region, or these plus either the higher or lower frequency subset of the remainingF1 harmonics. The results are consistent with an estimation procedure for theF1 peak which assigns greatest weight to the two most prominent harmonics in the first formant region.