This cross-sectional study assessed the influence of duration of residence in the United States on periconception dietary intake of pregnant Mexican immigrant women, using baseline data from Healthy Mothers on the Move, a randomized control trial conducted with 234 women from 2004 to 2006 in Detroit, MI. Average maternal age was 27.3±5.2 years (range=18 to 41 years) with 5.99±4.76 years of US residence (range=0 to 36 years). Women's usual dietary intake during the past 12 months was recorded on a validated food frequency questionnaire (17.3 weeks average gestation).