OBJECTIVES: We investigated whether African American mothers' upward economic mobility across the life course and having been of low birth weight are associated with the preterm birth of their children. METHODS: We performed stratified and multilevel logistic regression analyses on an Illinois transgenerational data set of African American infants (born 1989-1991) and their mothers (n = 11 265; born 1956-1976) with appended US Census income information. RESULTS: African American mothers with a lifelong residence in impoverished neighborhoods had a preterm birthrate of 18.7%. African American mothers with early life impoverishment who experienced low, modest, or high upward economic mobility by adulthood had lower preterm birthrates of 16.0% (rate ratio [RR] = 0.9; 95% confidence interval [CI] = 0.8, 0.9), 15.2% (RR = 0.8; 95% CI = 0.7, 0.9), and 12.4% (RR = 0.7; 95% CI = 0.6, 0.8), respectively. In multilevel logistic regression models of former low birth weight and non-low birth weight mothers aged 20 to 35 years, the adjusted odds ratio (95% confidence interval) of preterm birth for those who experienced high upward economic mobility (vs those with lifelong impoverishment) was 0.9 (0.5-1.6) and 0.7 (0.5-0.9), respectively. CONCLUSIONS: African American mother's upward economic mobility from early life impoverishment is associated with a decreased risk of preterm birth. However, consistent with fetal programming, this phenomenon fails to occur among mothers born at low birth weight.