The study objective was to measure breastfeeding rates and patterns in the Montérégie region of Québec. A survey of 632 mothers of 6-month-old infants was performed, of which 80% initiated breastfeeding, and 68% exclusively breastfed at birth. Breastfeeding rates progressively decreased with time: 63%, 56%, 51%, 44%, 39%, and 32% of mothers breastfed at 1, 2, 3, 4, 5, and 6 months, respectively. Among mothers breastfeeding at a given period, 62%, 57%, 48%, 35%, and 10% of women exclusively breastfed since birth for 1, 2, 3, 4, and 5 months, respectively. Exclusive breastfeeding for 6 months among the 200 women still breastfeeding was practically nonexistent. Introduction of nonhuman milk or solids was primarily responsible for the shift in patterns from exclusive to complementary feeding without passing through predominant breastfeeding. These findings confirm the need to prioritize effective hospital-based and community-based interventions to increase breastfeeding duration and exclusivity in the region.