Women's breast-feeding patterns are complex, and existing definitions of breast-feeding behavior do not capture this complexity adequately. We used results from a prior qualitative study to define trajectories for feeding during the first half of infancy, and then examined household-, maternal-, and infant-level determinants of these trajectories using logistic regression analysis. The 1472 women in the study cohort lived in rural Bangladesh and were participants in the Maternal and Infant Nutrition Intervention in Matlab trial. The 3 infant feeding trajectories included women who fed only breast milk and water [full breast-feeding trajectory (FBT)]; offered mixed feeding continuously when their babies were 0–4 mo old [continuous mixed feeding trajectory (CMFT)]; and practiced any other type of breast-feeding [intermittent feeding trajectory (IFT)], which was the normative feeding behavior in this community. In adjusted regression models, women who lived in rural areas [odds ratio (OR), 2.1; 95% CI, 1.2, 3.4], came from the poorest households (OR, 3.4; 95% CI, 1.5, 7.7), and offered prelacteal (OR, 1.7; 95% CI, 1.0–2.7) were more likely to be in the FBT. Women from the richest households (OR, 1.6; 95% CI, 1.1, 2.6), employed mothers (OR, 1.7; 95% CI, 1.1, 2.6), and older mothers (OR, 1.02; 95% CI, 1.0, 1.1) were more likely to be in the CMFT, and women with higher birth-weight infants (OR, 0.6; 95% CI, 0.4–0.8) were less likely to be in the CMFT. Thus, these trajectories were associated with distinct groups of women and these results provide information useful for developing interventions to improve breast-feeding practices.