Objectives To assess maternal dietary intake and adequacy at postpartum and to determine whether lifestyle characteristics and breastfeeding status are related to nutrient intakes. Methods We analyzed cross-sectional data from a convenience sample of 129 mothers at 18-mo postpartum, whose families were enrolled into a randomized toddler intervention trial, in the Lower Mainland, British Columbia, Canada. The Canadian Diet History Questionnaire II (C-DHQ II) was used to estimate usual dietary intake in the mothers during the preceding 12 months (i.e., between 6- to 18-mo postpartum). Implausible energy intakes were defined as <600 kcal/day or >3500 kcals/day, and excluded from analysis. Demographic and lifestyle characteristic data about the pregnancy and postpartum time period were collected using a questionnaire. Results Maternal mean (SD) age at birth was 33.5 (4.0) years and most women were of European (46%) or Asian (38%) ethnicity, and had Bachelor's degree or higher education (70%). About 75%, 88%, and 89% did not meet their dietary requirements (i.e., intake below the EAR) for fiber, potassium, and vitamin D intakes, from food only, respectively. Considering total dietary intake from food and supplements, the prevalence of dietary vitamin D inadequacy was 25%. Women of European ethnicity had higher vitamin D intake (median (IQR) in mg/1000kcal/day: 19.5 (7.26,101)) compared to Asian women (10.8 (3.87, 21.1); P < 0.05). Dietary vitamin D intake was higher in breastfeeding (i.e., providing breastmilk as primary milk source, i.e., ³2 times/day, to their 18-mo old toddlers) compared to non- or occasionally breastfeeding mothers (20.0 (10.5, 61.1) versus 14.9 (4.28, 26.7) mg/1000kcal/day; P < 0.05). Conclusions While most Canadian mothers in this sample met the EARs for most nutrients, the prevalence of dietary inadequacy was very high for vitamin D, potassium, and fiber. Some population groups may be especially at risk of developing nutrient deficiencies in this period of life characterized by postpartum recovery and transition; targeted public health strategies may be needed to address these deficiencies. Funding Sources This study is supported by The University of British Columbia, and the British Columbia Children's Hospital Research Institute, Canada, and is funded by Société des Produits Nestlé S.A.