The goal of this study was to examine whether listeners bilingual in Spanish and English would have difficulty in the discrimination of English vowel contrasts. An additional goal was to estimate the correlation between their discrimination and production of these vowels. Participants (40 bilingual Spanish- and English-speaking and 40 native monolingual English-speaking college students, 23-36 years of age) participated (M age = 25.3 yr., Mdn = 25.0). The discrimination and production of English vowels in real and novel words by adult participants bilingual in Spanish and English were examined and their discrimination was compared with that of 40 native monolingual English-speaking participants. Stimuli were presented within triads in an ABX paradigm. Novel words were chosen to represent new words when learning a new language and to provide a more valid test of discrimination. Bilingual participants' productions of vowels were judged by two independent listeners to estimate the correlation between discrimination and production. Discrimination accuracy was significantly greater for native English-speaking participants than for bilingual participants for vowel contrasts and novel words. Significant errors also appeared in the bilingual participants' productions of certain vowels. Earlier age of acquisition, absence of communication problems, and greater percentage of time devoted to communication contributed to greater accuracy in discrimination and production.