Obesity among pregnant women is becoming one of the most important women's health issues. Obesity is associated with increased risk of almost all pregnancy complications: gestational hypertension, preeclampsia, gestational diabetes mellitus, delivery of large-for-GA infants, and higher incidence of congenital defects all occur more frequently than in women with a normal BMI. Evidence shows that a child of an obese mother may suffer from exposure to a suboptimal in utero environment and that early life adversities may extend into adulthood. In September 2009, ILSI Europe convened a workshop with multidisciplinary expertise to review practices and science base of health and nutrition of obese pregnant women, with focus on the long-term health of the child. The consensus viewpoint of the workshop identified gaps and gave recommendations for future research on gestational weight gain, gestational diabetes, and research methodologies. The evidence available on short- and long-term health impact for mother and child currently favors actions directed at controlling prepregnancy weight and preventing obesity in women of reproductive ages. More randomized controlled trials are needed to evaluate the effects of nutritional and behavioral interventions in pregnancy outcomes. Moreover, suggestions that maternal obesity may transfer obesity risk to child through non-Mendelian (e.g. epigenetic) mechanisms require more long-term investigation.