Objective: The objective of this study was to examine and compare predictors of any breastfeeding and exclusive breastfeeding at 4 months postpartum between women residing in Canada for 5+ years and those new to Calgary and Canada. Methods: As part of a longitudinal study, women completed questionnaires about pregnancy experiences and breastfeeding practices. Bivariate analysis and multivariable logistic regression were conducted to identify the prevalence and predictors associated with breastfeeding outcomes at 4 months postpartum. Results: While numerous variables were found to be predictive of breastfeeding outcomes, the key factors were perceived prenatal physical health, pre-pregnancy BMI and smoking status prior to and during pregnancy. These three factors were consistently found to be predictive of both breastfeeding outcomes across all populations assessed. Conclusion: Although certain predictors of breastfeeding duration were similar between the groups, several were dissimilar, suggesting that these groups might benefit from different strategies to optimize breastfeeding outcomes.