Ambulatory blood pressure (ABP) monitoring offers a reliable method for determining blood pressure (BP) in children. The aim of this cohort study was to examine whether maternal preeclampsia is associated with elevated BP in an offspring. The study population consisted of 57 children born to preeclamptic mothers (PRE) and their 57 age- and sex-matched control subjects born to normotensive mothers (non-PRE). We examined the 24-h ABP at 12 y of age in the PRE and non-PRE children. Within the two groups, the association of anthropometric measures, plasma catecholamine (epinephrine [E], norepinephrine [NE]) concentrations, and ABP was examined. The PRE children had significantly higher mean 24-h systolic and diastolic ABPs than the non-PRE children. The same was true for the mean daytime and nighttime systolic and diastolic ABPs. The PRE boys had higher 24-h systolic ABP than the PRE girls. In the PRE children, high plasma E concentration and being born small for gestational age (SGA) predicted high systolic 24-h ABP in logistic regression analysis. In the non-PRE children, high current body mass index (BMI) and high plasma E concentration was associated with high systolic 24-h ABP. In conclusion, systolic and diastolic ABP values were elevated in the PRE children. High plasma E concentration and being born SGA were associated with high systolic 24-h ABP in the PRE children. Presumably maternal preeclampsia affects offspring via several mechanisms, including genetic ones and metabolic consequences of restricted intrauterine growth.