2 cases of infants who refused to nurse from a breast with a cancerous tumor are reported. The first 6 cases of this nature were described 28 years ago. Though this sign could lead to earlier detection of breast cancer in lactating women, it has not been accepted as such by the medical profession. Had the milk-rejection sign been recognized in our cases, breast cancer could have been diagnosed months earlier. We suggest that lactating women should be asked about the nursing habits of their babies and if there is milk-rejection, the breasts should be examined with special care.