OBJECTIVE: This study investigated how lexical effects account for word recognition in monolinguals versus bilinguals. DESIGN: Listener-specific error rate and familiarity rating of 200 NU-6 words were obtained. Lexical data (normative familiarity, frequency of occurrence, neighborhood density, and frequency of neighborhood competitors) for these words were obtained from the Hoosier mental lexicon. STUDY SAMPLE: Participants included 10 monolinguals and three groups of 10 bilinguals differing mainly in age of acquisition and length of schooling/working in English. RESULTS: Lexical effects were minimal for monolinguals' word recognition. Listener-specific familiarity rating correlated to error rate better than the Hoosier normative rating. Frequency of occurrence was the most significant lexical variable in accounting for bilinguals' measures and its effect was the greatest on bilinguals foreign born and educated. Age of English acquisition tended to affect familiarity rating, whereas length of schooling/working in English tended to affect error rate. CONCLUSIONS: Frequency of word occurrence significantly affects bilinguals' familiarity rating and error rate of the NU-6 words. Listener-specific familiarity rating should be obtained to best predict error rate on the test.