PIP: The areal difference in population structure is an important index to Korea's national development planning. To compare population structures among areas, this study utilized the Index of Relative Difference, the Index of Dissimilarity, and other population indices. Major findings follow. 1) Population aged 15-44 is concentrated in urban areas. Contrary to this trend, rural areas show a remnant phenomenon of population aged 50 and over. The aged dependency ratio is 10. It is 9 in rural areas, compared to 4.5 in urban areas. 2) Median age does not vary greatly among areas. It is 24.1 in cities, 24.2 in Up areas, 26.1 in Myon areas, and 24.9 in the islands. The aging index is significantly different among areas, with the figure at 6.6 in industrial cities, 10.1 in total cities, 16 in Up areas, and 26 in Myon areas. 3) The child-woman ratio shows a big difference among areas; it is 48.7 in industrial cities, 32.2 in other cities, 37.6 in Up areas, and 40.9 in the islands. 4) The Index of Relative Difference and the Index of Dissimilarity of Age Structure of the national base are 8.2 and 4.4 in total urban areas, 18.6 and 15.3 in industrial cities, and 21.6 and 11.6 in Myon areas, respectively. It shows apparent concentration of young population in urban areas and remnant phenomenon of aged population in rural areas, and shows more marked difference in female population than male population. 5) The marriage ratio is 40.3% in urban areas, contrary to 35.2% in Myon areas. The single ratio is 59.3% in urban areas and 64.3% in Myon areas. Sex difference of marriage is 33.5% among urban males and 46.9% among urban females, compared with 24.9% among males in Myon areas and 48.7% among females in Myon areas, showing a big areal difference in marriage structure. 6) Urban concentration of unmarried females delays marriage and contributes to the differences in sex ratio among areas. The proportion of males aged 25-29 to females aged 20-24 is 64 in urban areas, but 90 in rural areas. The proportion of males aged 30-34 to the females aged 25-29 is 35 in urban areas and 61 in rural areas, respectively. As a result, rural males have difficulty finding mates.