When two vowels are presented simultaneously, listeners can report their phonemic identities more accurately if their fundamental frequencies (F0’s) are different rather than the same. If theF0difference(ΔF0)is large, listeners hear two vowels on different pitches; if theΔF0is small the vowels are identified less accurately and they do not evoke different pitches. The present study used a matching task to obtain judgments of the pitches evoked by “double vowels” created from pairwise combinations of steady-state synthetic vowels /i/, /ɑ/, /u/, /æ/, and /ɚ/. OneF0was always 100 Hz; the otherF0was either 0, 0.25, 0.5, 1, 2, or 4 semitones higher. Experienced listeners adjusted theF0of a tone complex to assign pitch matches to 50-ms or 200-ms double vowels. ForΔF0’s up to two semitones, listeners’ matches formed a single cluster in the frequency region spanned by the twoF0’s. When theΔF0was 4 semitones, the matches generally formed two clusters close to theF0of each vowel, suggesting that listeners perceive two distinct pitches when theΔF0is 4 semitones but only one clear pitch (possibly accompanied by one or more weaker pitches) with smallerΔF0’s. When the duration was reduced from 200 ms to 50 ms, only a subset of the vowel pairs with aΔF0of 4 semitones produced a bimodal distribution of matches. In general, 50-ms stimuli were matched less consistently than their 200-ms counterparts, indicating that the pitches of concurrent vowels emerge less clearly when the stimuli are brief. Comparisons of pitch and vowel identification data revealed a moderate correlation between match intervals (defined as the absolute frequency difference between first and second pitch matches) and identification accuracy for the 200-ms stimuli with the largestΔF0of 4 semitones. The link between match intervals and vowel identification was weak or absent in conditions where the stimuli evoked only one pitch.