Given the detrimental influence of maternal overweight and obesity on reproductive and pregnancy outcomes for the mother and child, it is the position of the American Dietetic Association and the American Society for Nutrition that all overweight and obese women of reproductive age should receive counseling on the roles of diet and physical activity in reproductive health prior to pregnancy,during pregnancy, and in the inter conceptional period, in order to ameliorate these adverse outcomes. The effect of maternal nutritional status prior to pregnancy on reproduction and pregnancy outcomes is of great public health importance. Obesity in the United States and worldwide has grown to epidemic proportions, with an estimated 33% of US women classified as obese. This position paper has two objectives: (a) to help nutrition professionals become aware of the risks and possible complications of overweight and obesity for fertility,the course of pregnancy, birth outcomes, and short- and long-term maternal and child health outcomes;and (b) related to the commitment to research by the American Dietetic Association and the American Society for Nutrition, to identify the gaps in research to improve our knowledge of the risks and complications associated with being overweight and obese before and during pregnancy.Only with an increased knowledge of these risks and complications can health care professionals develop effective strategies that can be implemented before and during pregnancy as well as during the inter conceptional period to ameliorate adverse outcomes.