The purpose of this study was to assess nutrition knowledge during early and late postpartum in a sample of low-income and minority women, and to determine if that knowledge had any relationship to weight retention at 1-year postpartum. A questionnaire was developed and validated in a sample of 151 low-income new mothers. This instrument was then administered to a separate sample of mothers (n=140) of similar demographics to assess nutrition knowledge at 0 to 1 days and 12 months postpartum. In addition, a survey of nutrition information sources was administered at both time points. Nutrition knowledge was compared with 12-month postpartum weight retention and demographic variables. Women who retained less than 5% of weight gained during pregnancy had greater knowledge of nutrition at 0 months (53% vs 49%, P<0.05) and 12 months (55% vs 51%, P<0.05) than those who retained 5% or more of weight gained during pregnancy. Whites had higher nutrition knowledge scores than non-Hispanic blacks and Hispanics. Women who lactated 6 months or more had more knowledge than those who lactated less than 6 months. Higher knowledge test scores were observed among women who used the Internet and books/magazines as their source for information. These results indicate that assessment of nutrition knowledge in early postpartum can identify women at risk for significant weight retention.