The changes of selenium and zine contents of transitional milk and mature milk at 7 and 60 days postpartum were comparatively studied on 20 Korean lactating women. the selenium and zinc contents of transitional milk and mature milk were analyzed by atomic absorption spectrophotometer after wet-digestion. The mean selenium contents wer 12.2$mu extrm{g}$ /ι and 11.5$mu extrm{g}$/ι at 7 and 60 days postpartum, respectively. The mean zinc contents decreased significantly from 4.23mg/ι at 7 days to 1.62mg/ι at 60 days postpartum (p<0.05).