Skin aging is important medical and social problem in modern world. A goal of present work was to estimate changes in the number of fibroblasts and PCNA-positive fibroblasts in human dermis at different ages. Total number of fibroblasts per unit area was counted in slides stained with haematoxylin and eosin. PCNA which is present in cells being in the cell cycle was revealed immunohistochemically. Results showed a decrease in a total number of fibroblasts in dermis through aging. The number of PCNA-positive fibroblasts in dermis is also decreased with progression of age. It may be concluded that age-related decrease in dermal fibroblasts number is associated with diminished proliferation of these cells. Causes which lead to a decrease in proliferation are not clear, and new researches are needed to reveal them.