The association between maternal gestational diabetes (GDM) and manifestations of metabolic syndrome among Caucasian adolescents was studied with data from the population-based Northern Finland 1986 Birth Cohort. This is a longitudinal cohort study from early pregnancy until offspring age 16 years and includes data from a risk group-based GDM screen of pregnant mothers by an oral glucose tolerance test. Metabolic outcomes were compared between the offspring of women with GDM (OGDM; n = 95) and reference group offspring (n = 3,909). The prevalence of overweight was significantly higher in the OGDM group (18.8 vs. 8.4%; P