Rates of breastfeeding in women with pregestational diabetes, and in particular type 2 diabetes are poorly characterised. Small studies suggest they are lower than the general population despite clear evidence of benefit in this population and the vast majority of women intending to breastfeed. This is a complex problem due to the contribution of different aetiologies including social and educational factors, iatrogenic factors associated with management of pregnancies in women with diabetes, as well as the potential of underlying metabolic abnormalities to interfere with copious milk secretion “secretory activation” and consequent lactation establishment. This presentation will review the physiology and endocrinology of lactation and hypothesise how insulin resistance and metabolic syndrome may play a role failure to successfully establish lactation in this population. It will also introduce the “Breastfeeding in Mothers with Type 2 Diabetes Study” (BFT2DM), currently in progress at the Royal Brisbane and Women’s Hospital which aims to assess the rate of lactation establishment in women with type 2 diabetes and the correlation between delayed secretory activation (milk ‘coming in’) and successful lactation establishment by measuring the change in electrolyte concentrations in colostrum over time. Finally, it will discuss practical changes that clinicians can make to improve breastfeeding outcomes in this group, while acknowledging the need for further research to guide evidence-based care.