The purpose of this study was to estimate the mineral intakes and serum mineral levels of pregnant and lactating women. The subjects consisted of 34 non-pregnant, 56 pregnant and 20 lactating women. Nutrients intakes were investigated by the 24-hr recall method, and serum major and trace minerals were analyzed by the ICP-spectrometry. Calcium (Ca) and zinc (Zn) intakes were observed lower than RDA especially for both pregnant and lactating women. Iron (Fe) intake of pregnant women was 85-139% RDA through Fe supplementation, and that of lactating women was lower than RDA. Compared with non-pregnant women, the pregnant women had similar Ca intake and higher magnesium (Mg) intake. Comparing with the non-pregnant women, serum Ca level in pregnancy was lower, and that of lactating women was not significantly different. Serum phosphorus and Mg levels were not significantly different among the groups. Serum Fe level of pregnant and lactating women was lower than that of the non-pregnant women. Serum Zn level of pregnant women was lower than those in the lactating and non-pregnant women. Serum copper level decreased as the pregnancy progressed. Serum sodium (Na) level was higher in 2nd- and 3rd trimester and potassium (K) level was higher in 3rd trimester and lactating period than other groups. Na/K ratio was not significantly different among the groups. During all periods, there was no correlation between dietary intakes and serum levels in each minerals. Serum Ca level positively corrleated with serum Mg level, especially in 3rd trimester and lactating women. In general, serum mineral levels in pregnancy were changed compared to the levels in non-pregnancy and restored in lactation to the levels for non-pregnancy. (Korean J Community Nutrition 10(1): 59~69, 2005)