The aim of this study was to examine the pathways that link mothers' early life socio economic status (SES) and mothers' experience of childhood maltreatment with birth weight among their later born offspring. Data were drawn from a nationally representative longitudinal survey of school-aged respondents, initially enrolled during adolescence in Wave I (1994-1995) and Wave II (1996) of the National Longitudinal Study of Adolescent Health and followed-up in adulthood in Wave III (2001-2002). Data on offspring birth weight were obtained from nulliparous females (N = 1,897) who had given birth between Waves II and III. Analyses used structural equation modeling to examine the extent to which early life maternal risk predicted offspring birth weight, and demonstrated that maternal childhood SES and maternal childhood maltreatment predicted offspring birth weight through several mediated pathways. First, maternal adolescent substance use and prenatal cigarette use partially mediated the association between maternal childhood SES and offspring birth weight. Second, maternal adolescent depressive symptoms and adult SES partially mediated the association between maternal childhood SES and offspring birth weight. Third, adult SES partially mediated the association between maternal childhood SES and offspring birth weight. Fourth, maternal adolescent substance use and prenatal cigarette use partially mediated the association between maternal childhood maltreatment and offspring birth weight. Finally, maternal adolescent depressive symptoms and adult SES partially mediated the association between maternal childhood maltreatment and offspring birth weight. To our knowledge, this is the first study to identify maternal childhood maltreatment as an early life risk factor for offspring birth weight among a nationally representative sample of young women, and to demonstrate the mechanisms that link childhood SES and maltreatment to offspring birth weight. These findings suggest the importance of designing and implementing prevention and intervention strategies to address early life maternal social conditions in an effort to improve inter generational child health at birth.