Using human autopsy skin specimens from 144 Caucasian males, 172 Japanese males and 103 Japanese females at different ages ranging from infancy to 94 years, age changes in cellularity, vascularity and proportions of several cell types in connective tissue of the dermis were studied. In the youngest age group, cellularity in the dermis was high, and the cells were constituted almost entirely by fibroblasts and macrophages. Cellularity in the dermis decreased with age. The number of fibroblasts with dark nuclei increases in older age groups. The number of demonstrable mast cells also increases. The number of papillae in a given area decreases remarkably in the later decades. There is an apparent increase in percentage of lymphocytes with age. However, the increase is not significant according to the strict analysis by the Tukey method. With the exception of the number of fibroblasts with dark nuclei, the differences in number of all types of cells between Japanese males and females are not significant. However, differences between 2 races (Caucasian males and Japanese males) are significant statistically with a few exceptions. The difference in the age change in number of several types of cells, as between the 2 races, are significant.