Breast-fed infants in Bangladeshi villages were weighed at 1, 2, 6, 9 and 12 months. The concentrations of zinc and copper in the breast milk were measured and the daily intake of these elements calculated. Breast milk Zn concentration decreased over the year but was comparable with that found in developed countries. The calculated daily intake decreased from 17.7 to 8.0 mumol (10-30% of recommended dietary allowances (RDA); National Academy of Sciences, 1980). Breast milk Cu concentration also fell over the year and was lower than that reported from developed countries. Calculated daily Cu intake was 1.95-2.63 mumol (RDA 7.81-15.63 mumol). Deficiencies of trace elements may therefore be a problem in poorly nourished communities where breast feeding is continued for several years with only small amounts of additional food. Breast milk may not be adequate as the only source of infant nutrition after the first few months of life in Bangladesh.