Obesity is considered a public health problem worldwide. Evidence from epidemiologic studies has shown that early undernutrition may be a determinant of obesity later in life. Longitudinal studies are scarce in the setting of low- and middle-income countries. In Pelotas, southern Brazil, a birth cohort has been followed since 1982. Between 2004 and 2005, 4297 members of this cohort were interviewed. The aim of this study is to describe the association between maternal anthropometry and offspring BMI and waist:height ratio (WHtR) at 23 y of age in individuals from the 1982 Pelotas birth cohort. Independent variables included maternal prepregnancy BMI and maternal height, obtained in 1982. The BMI and WHtR of the offspring at 23 y of age were the outcomes. The analysis was stratified by sex and restricted to those cohort members belonging to the lower income group. Multivariable linear regression was adjusted for potential confounding or mediating factors according to a hierarchical framework. For each unit of maternal prepregnancy BMI, the offspring BMI increased 0.65 and 0.63 kg/m(2) in men and women, respectively (P < 0.001). Maternal prepregnancy BMI was directly associated with offspring WHtR in both sexes (P < 0.001). On the other hand, maternal height was not associated with offspring BMI or WHtR. In conclusion, our study suggests that maternal anthropometry is associated with the offspring BMI and WHtR at 23 y of age.