The objective of this study was to analyze the status of large birth weight(macrosomia) and factors affecting incidence of macrosomia in Korea The data was collected f개m vital statistics of National Vital Statistical Office of Korea Total birth cases were 711,129 during 1994. 1. The largest proportion of birth weight was 3.00~3.49㎏ group(44.2percent in male and 48.2percent in female). The incidence of low birth weight was higher in female(3.1percent) than that of male(2.5percent). The incidence of macrosomia was 8.2percent in male and 4.8percent in female. Mean birth weight by sex was 3.4031㎏ in male, 3.3001㎏ in female and 3.3553㎏ in both sex. 2. The distribution of normal birth weight(2.50~3.99㎏) by maternal age was 92.1percent in under 20 years old and 88.8percent in aged 40 and over. The incidence of low/high birth weight increased with maternal age. Mean birth weight by maternal age group in both sex was 3.3710㎏ in 30~34 age group, and 3.2808㎏ in under 20 years old Mean birth weight increased with increasing maternal age. 3. The proportion of normal birth weight decreased with ranking birth order from 1st to 4th order. The incidence of low/large birth weight increased with ranking birth order. Mean birth weight by birth order in both sex was 3.3319㎏ in 1st birth order, 3.3689㎏ in 2nd, 3.4276㎏ in 3rd and 3.4266㎏ in 4th and over. 4. The incidence of macrosomia was higher in male than that of female. The risk for macrosomia in male was 1.76(odds ratio) compared with female infant The odds ratios for risk of macrosomia were 1.05 in 2nd birth, 2.Q7 in 3rd and 2.45 in 4th and over compared with the incidence of macrosomia in 1st birth order. The incidence of macrosomia by maternal age in both sex increased with increasing maternal age; from 4.5 in under 20 years of age to 7.7percent in aged 40 and over. The odds ratios for risk of macrosomia in maternal age were 0.76 in under 20 years, 1.13 in 20~29 years, 1.37 in 30~34 years, 1.42 in 35~39 years and 1.35 in aged 40 and over compared with the incidence of macrosomia in women 20 to 24 years old.