BACKGROUND: Many breastfeeding women have concerns about their milk supply; 'not enough milk' is the most common reason women give for stopping breastfeeding, however their concern is often unwarranted. OBJECTIVE: The article describes the process of history taking and examination of mother and infant to determine if the mother's milk supply is adequate, the causes of insufficient milk supply, and possible investigations and management. DISCUSSION: Insufficient milk supply may be secondary to maternal conditions such as postpartum haemorrhage or breast reduction surgery, or infant factors such as tongue-tie or ill health. In many cases, milk supply can be increased by frequent, regular milk removal. Medication to increase milk supply (galactogogues) such as domperidone, may also play a role. General practitioners can provide reassurance if milk supply is adequate, or can assist in resolving the problem if milk supply is low.