Self reports from 1,645 Latino mothers of Mexican descent who participated in the Hispanic Health and Nutrition Examination Survey (HHANES) were used to relate the birthweight of their infants to the HHANES acculturation index. After controlling for parity, a one point increase on the acculturation scale was found to be associated with a 1.19 (95% CI = 1.05, 1.34) increase in risk of maternal low birthweight (LBW) (1.98 risk increase for four points). The estimated relative risk increased to 1.34 (1.12, 1.60) with controls for age at interview, wealth, city size, and years of education; controlling for current smoking status reduced the relative risk to 1.31. US-born respondents were also at increased risk relative to Mexican-born, but this relation was explained by acculturation. The effect of education was found to depend on level of acculturation. Years of education was unrelated to risk among the Mexican-oriented, while increased education was associated with reduced risk in the US-oriented. These results suggest that factors associated with a Mexican cultural orientation may be protective against the risk of LBW.