To investigate associations between maternal pregnancy hyperglycemia, gestational diabetes mellitus (GDM), and offspring adiposity. We evaluated these associations in a longitudinal study of 421 mother-daughter pairs at Kaiser Permanente Northern California. Maternal pregnancy glucose values were obtained from maternal medical records. Outcomes included three measures of girls’ adiposity, measured annually: (1) ?85th age-specific percentile for BMI; (2) percent body fat (%BF); and (3) waist-to-height ratio (WHR). Adjusting for maternal age at delivery, race/ethnicity, pregravid BMI, girl’s age, and girl’s age at onset of puberty, having a mother with GDM increased a girl’s risk of having a BMI ?85th percentile or having %BF or WHR in the highest quartile (Q4), compared with those in the lowest quintile of blood glucose (odds ratio [OR] 3.56 [95% CI 1.28-9.92]; OR 3.13 [95% CI 1.08-9.09]; and OR 2.80 [95% CI 1.00-7.84], respectively). There was a significant interaction between the presence of GDM and pregravid BMI; girls whose mothers had both risk factors had the highest odds of having a BMI ?85th percentile (OR 5.56 [95%CI 1.70-18.2]; Q4 %BF, OR 6.04 [95% CI 1.76-20.7]; and Q4 WHR, OR 3.60 [95% CI 1.35-9.58]). Similar, although weaker, associations were found in the association between hyperglycemia and offspring adiposity. Girls who were exposed to maternal GDM or hyperglycemia in utero are at higher risk of childhood adiposity; risk increases if the mother is overweight or obese. Screening and intervention for this high-risk group is warranted to slow the intergenerational transmission of obesity and its sequelae.