The research undertaken in this study utilized a case-control group nested within a prospective cohort which was followed for the first 3 months postpartum. Mothers with mastitis and their controls were requested to complete a self-report questionnaire designed to investigate the association between the potential risk factors, identified from the literature, and lactation mastitis. Logistic regression analyses of the possible risk factors were performed separately for mothers who had not breastfed previously and those mothers who had breastfed at least one infant prior to this lactation. Analysis showed blocked duct(s) and increased levels of stress were the significant predictors for mastitis in mothers who had breastfed a previous infant and blocked duct(s), restriction from a tight bra, attachment difficulties, and nipple pain during a feed were the significant predictors for mastitis in first time breastfeeding mothers.